abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
high-resolution thermospheric mass density (tmd) measurements from low earth orbit (leo) satellites are valuable to accurately estimate the short-term atmosphere abrupt disturbances, triggered by magnetospheric forcing. a good characterization of tmd variation ahead of the arrival geomagnetic storms can benefit leo ope... | thermospheric mass density variations based on grace-fo during the ascending phase of solar cycle 25 |
cosmogenic isotopes, including 14c, 10be, and 7be, are produced in the earth's atmosphere under the effect of cosmic rays. the rate of their production is determined by several factors, such as the intensity of primary galactic cosmic rays, the level of solar activity, and the strength of the earth's magnetic field. ch... | approximately 2400-year cycle in the concentration of cosmogenic radionuclides: sources of variations |
we study the solar-cycle variation of the zonal and meridional flows in the near-surface layers of the solar convection zone from the surface to a depth of about 16 mm. the flows are determined from sdo/hmi dopplergrams using the hmi ring-diagram pipeline. the zonal and meridional flows vary with the solar cycle. bands... | subsurface zonal and meridional flows from sdo/hmi |
the polar cap magnetic activity index (pc) was approved by iaga as an index characterizing the solar wind energy input into the magnetosphere. relation of the pc index to solar wind parameters and solar activity during 23/24 solar cycles has been studied in paper (troshichev et al., 2021, https://doi.org/10.1029/2020ja... | reply to comment by stauning on "the pc index variations during 23/24 solar cycles: relation to solar wind parameters and magnetic disturbances" |
short-term variations of the solar mean magnetic field (smmf) were investigated through re-analyzing the data from the wilcox solar observatory during the last four solar activity cycles using continuous wavelet transforms. we demonstrated the time-variable characters of short-term periods of smmf. our results indicate... | phase relationship between the relative sunspot numbers and solar mean magnetic field |
the mars advanced radar for subsurface and ionospheric sounding (marsis) on board the mars express spacecraft has been probing the topside of the ionosphere of mars since june 2005, covering currently almost one solar cycle. a good knowledge of the behaviour of the ionospheric variability for a whole solar period is es... | scale height variations with solar cycle in the ionosphere of mars |
we report the first high-resolution (with intervals ca. 20-50 years) late-holocene (4200 yr bp) pollen record from lake teletskoye, altai mountains, obtained from the underwater ridge of sofia lepneva in 2006 (core tel 2006). the study presents (i) the results of palynological analysis of tel 2006; (ii) the results of ... | mid-late holocene climate and vegetation in northeastern part of the altai mountains recorded in lake teletskoye |
relativistic (e > 0.6, > 2.0, and > 4.0 mev) electrons at geosynchronous orbit during solar cycle 23 are well-correlated with the intervals of high-intensity, long-duration, continuous ae activity (hildcaa) events. cluster-4 passes were examined for electromagnetic chorus waves in the 5 < l < 10 and 0 &l... | intense auroral activity (hildcaas) observation as a predictor of radiation belt relativistic electrons |
in the present work, the day-time variation of the characteristic frequency fof2 of the ionosphere is studied with regard to changes of the seismic activity of the earth. used are observations of the vertical ionospheric sounding station 'tokyo' registered in the years 1957-1990. in the analysis, data of the ionopsheri... | day-time dependence of fof2 variations connected with earthquakes |
phenomenon of the solar variability is primarily driven by the evolution of magnetic fields on both small and global scales. because connection between the dynamo processes on different scales remains unclear, we consider them separately. in particular, we analyze 1) a global dynamo model, which is reduced to a dynamic... | solar dynamo on small and global scales |
acoustic mode parameters are generally used to study the variability of the solar interior in response to changing magnetic activity. while oscillation frequencies do vary in phase with the solar activity, the mode amplitudes are anti-correlated. now, continuous measurements from ground and space allow us study the ori... | response of solar oscillations to magnetic activity in cycle 24 |
the ionosphere is a highly complex plasma containing electron density structures with a wide range of spatial scale sizes. large-scale structures with horizontal extents of tens to hundreds of km exhibit variation with time of day, season, solar cycle, geomagnetic activity, solar wind conditions, and location. whilst t... | modelling large-scale structures in the high-latitude ionosphere using 15 years of data from the eiscat svalbard radar |
the temporal variations of the total or integrated radiance of the k-corona of the sun were found to be correlated with solar activity (or sunspot) cycle in some previous studies. in this paper, we address the question on how the global electron content of the corona varies with the solar cycle, and relates to the evol... | variations of the electron density of coronal streamers with solar cycle observed with stereo/cor1 |
periodic behaviors of solar magnetic indicators might provide a clue for the understanding of solar dynamic processes. combining with a lomb–scargle periodogram, the concentration of frequency and time via a multitapered synchrosqueezed transform is applied to investigate the periodic variations of modified coronal ind... | periodic variations of solar corona index during 1939–2020 |
the study of the quiescent-sun (non-flaring) periods and their plasma properties relative to flaring times is crucial for understanding solar activity and coronal heating. this analysis of dual aperture x-ray solar spectrometer (daxss) data uses soft x-ray (sxr) spectra obtained with 9-second cadence between 15:00:45 u... | temperature, emission measure, and elemental abundances of the quiescent sun from daxss spectra |
the helium abundance to hydrogen (ahe = nh/nhe*100 %) varies significantly in different layers of the sun. the ahe also varies with solar cycle activity and solar wind speed. the changes in its behavior in the last four solar cycles were not comprehensively known. we show that ahe variations are distinctively different... | investigations on helium abundance in background solar wind and interplanetary coronal mass ejections |
we apply time-distance helioseismology to mdi and hmi medium-degree dopplergrams covering may 1996-april 2017, i.e., 12-yr of cycle 23 and 9-yr of cycle 24. our data analysis takes several systematic effects into account, including the p-angle error, surface magnetic field effects, and the center-to-limb variations. fo... | twenty-one-year helioseismic measurement of solar meridional circulation from soho/mdi and sdo/hmi: anomalous northern hemisphere during cycle 24 |
interstellar pickup ions constitute a charged particle population that originates from interstellar neutrals inside the heliosphere. they are produced by photoionization, charge exchange with solar wind ions, and electron impact ionization (ei). once ionized, they are picked up by the interplanetary magnetic field (imf... | modeling and observation of interstellar he+ pickup ions in the inner heliosphere |
the sunspot number is the most used index to quantify the solar activity. nevertheless, the sunspot is a syn- thetic index and not a physical index. therefore, we should be careful to use the sunspot number to quantify the low (high) solar activity. one of the major problems of using sunspot to quantify solar activity ... | the periodicity of grand solar minimum |
the cyclic behavior of the solar magnetic field has been known for centuries and the 11-year solar cycle is one of the most important features directly visible on the solar disc. using sunspot records it is evident that the length of this cycle is variable. a hypothesis of an inverse relationship between the average so... | reconstructing the 11-year solar cycle length from cosmogenic radionuclides for the last 600 years |
in this study we analyze the abundances of suprathermal heavy ions in 75 corotating interaction region (cir) events between january 1st 1995 and december 31st 2008. we correlate the heavy ion abundances in these cirs with those measured in the solar wind and suprathermal populations upstream of these events. our analys... | abundance and source population of suprathermal heavy ions in corotating interaction regions |
we present the compositional variation in the solar energetic particle (sep) population in the inner heliosphere over two solar cycles using data from the ulysses heliospheric instrument for spectra, composition, and anisotropy at low energies (hiscale) and advanced composition explorer (ace) electron proton alpha moni... | solar energetic particle composition over two solar cycles as observed by the ulysses/hiscale and ace/epam pulse height analyzers. |
properties of helioseismic acoustic oscillations (p modes) are modified by flows and magnetic fields in the solar interior, with frequencies, amplitudes and damping rates all varying systematically through the solar cycle. crucially, now, we have a long enough baseline of helioseismic data to compare of the different a... | helioseismic insights into the generation and evolution of the sun's internal magnetic field |
incident solar x-ray and extreme ultraviolet photons ionize atoms and molecules in a planet's atmosphere, generating a weakly ionized plasma layer called an ionosphere. the characteristics of a planet's ionosphere depend on its atmospheric composition, surface gravity, and incident solar radiation, among other factors.... | solar cycle variations of the ionospheres of venus and mars |
cmes are episodic expulsion of plasma and magnetic fields from sun into heliosphere. cmes can be classified, based on their speeds, as slow cmes and fast cmes. we find that slow cmes and fast cmes behave differently in two cycles. while fast cmes seem to follow the sunspot variations, slow cmes have much flatter distri... | kinematics of slow and fast cmes in soar cycle 23 and 24 |
the large scale (dipolar) solar magnetic field is known to be asymmetric in the north-south direction. according to spacecraft observations, the southern hemisphere magnetic field has been stronger during the five last solar activity cycles. magnetic flux balance requires the northern magnetic field to cover a wider ar... | long-term heliospheric current sheet oscillation |
solar activity predictions using the data assimilation approach have demonstrated great potential to build reliable long-term forecasts of solar activity. in particular, it has been shown that the ensemble kalman filter (enkf) method applied to a non-linear dynamo model is capable of predicting solar activity up to one... | application of synoptic magnetograms for prediction of solar activity using ensemble kalman filter |
hisaki is an earth orbiting extreme ultraviolet spectroscope (exceed) which was launched on 14 september 2013. hisaki has carried out unprecedented continuous observation of io plasma torus and jovian aurora and found responses of the jovian magnetosphere to volcanic activities of io and the solar wind. in the spring o... | io plasma torus and jovian aurora activity during the juno era: current status of hisaki/exceed |
temperature cycles with periods > 2000 yr, including peaks of order 6000 yr, has been reported in 14c proxy records in sediments for fennoscandia (olsen et al, 2005) and in glacier geochemistry for the greenland ice-sheet (mayewski et al, 1997, 2004). similar spectral peaks are also seen in 14c and 10be isotopes in ... | holocene 6000-yr climate cycles in temperate and sub-tropical sst records - a cosmic ray connection? |
ionosphere is a layer of the atmosphere which is an integral part of whole geomagnetic and geological framework. ionosphere responds to solar euv radiation by varying within the diurnal 24-hour period, seasonal periods and annually and over the 11-year cycle of solar activity. therefore, relying on the evidence that th... | ionospheric response during the equinox and the solstice periods over turkey |
the skewness of the monthly distribution of gse latitudinal angles of interplanetary magnetic field (imf) observed near the earth (sk) is found to show anti-correlation with sunspot activity during the solar cycles 20-24. sk can be considered as a measure of the predominant polarity of north-south component of imf (bz ... | on the association of predominant polarity of north-south component of imf in the gse system near 1 au with solar polar magnetic fields during 1967-2020 |
after a lull lasting more than 60 years of seemly uniform solar minima, the solar minimum of solar cycle 23 came as a great surprise due to its depth, duration, and record lows in a wide variety of solar activity indices and solar wind properties. one of the consequence of such an event is the revival of the interest i... | the minimum of solar cycle 23: as deep as it could be? |
geomagnetic field observations are a superposition of contributions from the geodynamo in the core, remanent or induced magnetic fields in the lithosphere, and the magnetic signals produced by current systems in the ionosphere and magnetosphere. disentangling all of them remains a challenge. geomagnetic activity indice... | developing a new magnetospheric current index characterising hourly to decadal variations |
we present in this work the development of a solar data assimilation method based on an axisymmetric mean field dynamo model and magnetic surface data. our mid-term goal is to predict the solar quasi cyclic activity. we focus on the ability of our variational data assimilation algorithm to constrain the deep meridional... | towards estimating the solar meridional flow and predicting the 11-yr cycle using advanced variational data assimilation techniques |
we estimate the contribution of the systematic component of the earth's main magnetic field (mmf), i.e., the main dipole, to the secular variation in the midlatitude polar auroras based on the archived data. it is found that the main features of the variations in the magnetic moment (mm) of the main dipole in 1600-1909... | variations in the auroral activity and main magnetic field of the earth over 300 years (1600-1909) |
during the declining phase of the current quiet solar cycle, heliospheric activity has suddenly and drastically increased starting from a simple sunspot in active region (ar) 2673, which transformed into a complex region with three x-flares accompanied by several earth-directed coronal mass ejections (cme) from 4th to ... | the september 2017 events and their imprints at earth and mars |
we examine solar wind intervals with alfvénic fluctuations in 1995-2011. the annual number, the total annual duration and the average length of alfs vary over the solar cycle, having a maximum in 2003 and a minimum in 2009. alfs are most frequent in the declining phase of solar cycle, when the number of high-speed stre... | occurrence, solar cycle evolution and effects of alfvénic fluctuations |
the intermediate-degree mode parameters are used to study the variability of solar oscillations and their dependence on the magnetic-activity. we use uninterrupted observations from the 6-site network, global oscillation network group (gong), for about 20 years that covers a period from the minimum of cycle 23 to the d... | helioseismic mode parameters from 20 years of global oscillation network group (gong) observations |
the electrodynamics of the earth's ionosphere is driven mainly by the e region electric field. the study of the electric field variations is important in context of understanding the response of ionosphere to various solar and geomagnetic conditions. no direct methods are available for the continuous measurement of the... | study of the variability in the ionospheric zonal drift and electric field - an investigation of dynamo region using hf radar at 18 mhz over equator |
uninterrupted helioseismic data from michelson doppler imager (mdi) onboard solar and heliospheric observatory (soho) and from helioseismic and magnetic imager (hmi) onboard solar dynamics observatory (sdo) have provided unique information about flows and structures evolving on various temporal and spatial scales insid... | helioseismic monitoring of solar subsurface dynamics and activity |
the properties of the solar wind vary with the solar cycle, evolving across time and latitude. the solar wind density, pressure, and speed change with solar activity which has been shown to affect flows within the heliosheath, and subsequently, the overall structure of the heliosphere. many studies have shown the impor... | time-dependent models of the heliosphere |
the temperature variations of the corona and its individual surface features as a function of the solar cycle are an interesting and important aspect of understanding the physics of the sun. to study the temperature variations, we have used the full-disk soft x-ray images of the corona obtained from hinode/x-ray telesc... | solar soft x-ray irradiance variability, ii: temperature variations of coronal x-ray features |
intense fluxes of electrons from the earth's radiation belt (erb) with energies of tens and hundreds of kev can penetrate to low altitudes at low latitudes outside the south atlantic anomaly. this region is known as a forbidden zone of quasi-trapped energetic particles. flux enhancements of energetic electrons in the f... | solar-cycle variations of forbidden energetic electrons enhancements |
the pair of the grace (gravity recovery and climate experiment) satellites has been orbited in a near circular and polar orbit during the 15.5-year mission that began from march 17, 2002. the grace-follow-on mission, with a scheduled launch in april 2018, will use the same orbit configuration to continue monitoring the... | thermospheric density variations from analysis of grace accelerometer data |
the sun's outer atmosphere, known as the corona, contains a complex system of magnetized plasmas of varying temperatures that are in constant motion. the focus of this study is on two opposite modes of mass transport in the corona: coronal jets that eject (hot and cool) plasma upward and coronal rain that drains cold p... | on the mass transport in the solar corona: hot jets shooting up and cold rain falling down |
magnetic storms are undoubtedly among the most important phenomena in space physics and also a central subject of space weather. the hellenic geomagnetic array (enigma) is a network of 4 ground-based magnetometer stations in the areas of thessaly, central greece, peloponnese and crete in greece that provides geomagneti... | wavelet spectral analysis of the enigma magnetometer array and solar wind time series around the strongest magnetic storms of solar cycle 24 |
not only is the number of sunspots variable, but so is the timing of the minima and maxima of the sunspot counts. at the end of the 18th century, the sunspot cycle began sooner and sooner, and then early in the 18th century regained its earlier phase as the sun entered the dalton minimum. recently, the sun has repeated... | what is the time series of sunspot numbers telling us about the solar dynamo? |
coronal mass ejections (cmes) are the main source of strong space weather disturbances at earth and other locations in the solar system. while their impact is largely determined by their dynamic pressure and magnetic field, interactions with other cmes can significantly alter their individual characteristics and enhanc... | a study of the role of cme-cme interactions on cme geo-effectiveness with euhforia |
our study is focused on the analysis of the geomagnetic variability of the h and z components at different local times and at midlatitude during high solar activity. the variations of geomagnetic field can be from scale of seconds to millions of years and they can be periodic or random and its strength can vary from fe... | seasonal variation of geomagnetic field and tec at mid latitudes |
enhancements of electrons in the slot region attracts a special interest for planning and operations of space missions due to detrimental effects posed to spacecrafts by energetic particles. the aim of this study is to analyse variability of the radiation environment in the slot region during the period from 1998 to 20... | response of the electron slot region to space weather conditions |
solar wind dynamic pressure pulse (dpp) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-earth space environment. in this investigation, we first present a statistical study on the properties of strong dynamic pressure p... | strong solar wind dynamic pressure pulses during solar cycle 23 and their impacts on geosynchronous magnetic fields |
the solar oblateness results from distortion processes due to several phenomena inside the sun but also induced by the centrifugal potential of the surface rotation. this fundamental parameter is therefore of great scientific interest, but its measurements for more than a century are still very controversial, whether f... | solar oblateness variations in phase with the 22 year-magnetic cycle |
it has been reported (preminger et al. 2011) that the disk-integrated contrast of visible solar continuum images varies out of phase with the solar cycle, in contrast to faculae dominated models of total solar irradiance and soho/virgo measurements of the visible continuum but in qualitative agreement with sim measurem... | sensitivity of long-term photometric trends to center-to-limb profile variations |
the western hemisphere has been recording sunspot numbers since galileo discovered sunspots in the early 17th century, and the roughly 11-year solar cycle has been recognized since the 19th century. however, predicting the strength of any particular cycle remains a relatively imprecise task. this project's aim was to u... | a geomagnetic precursor technique for predicting the solar activity cycle |
in this work, we have a well-known event in scientific literature used to illustrate our investigation on the viability of the solar diameter variation be a precursor for the occurrence of sets of coronal mass ejections, and thus, for geomagnetic storms, as noted in previous works of our group, but now, in a time scale... | analysis of the solar diameter variations at july, 1986 and the geomagnetic storm of march, 1989 |
the dominant form of mass and energy transport between the sun and the ice giant magnetospheres of uranus and neptune remains an open question. predictions based on theory suggest that a combination of the weaker internal magnetospheric plasma sources and significantly tilted magnetic dipole fields of uranus and neptun... | solar cycle dependence of solar wind coupling at the ice giants |
applying principal components analysis (pca) to the full-disk synoptic maps of solar magnetic field variations obtained by wilcox solar observatory in solar cycles 21-24 we derive 4 pairs of eigen values and eigen vectors (zharkova et al, 2015) and analytical expressions as the sums of periodic sin and cosine functions... | solar magnetic field oscillations and activity on a millennium timescale derived with principal component analysis |
solar and terrestrial activities reveal periodic variations in large range of time scales. analysis of periodicities in the sun and interplanetary medium exhibits various aspects of solar and terrestrial physics. periodicities in solar and terrestrial parameters are classified into short, mid and long-term types on the... | analysis of short term periodic variation in solar and terrestrial parameters using wavelet based techniques |
the shift of the heliospheric current sheet (hcs) can be judged by the correlation between polarities of the interplanetary magnetic field (imf) observed near the earth. here the imf polarities which were reconstructed from the geomagnetic data of the mid-latitude stations beginning from 1844 are studied. the correlati... | secular variations of a shift of the heliospheric current sheet |
this study aims look into the long-term ionospheric scintillations activities during quiet and disturbed geomagnetically periods over the low latitude region in the brazilian sector. the research was carried out from single-frequency gps receivers acquired during 17 years on the amplitude scintillation data through glo... | morphology of the ionospheric scintillations over low latitude region during geomagnetically quiet and disturbed periods |
meridional flow plays an important role in solar dynamo, which drives solar cycles of magnetic field variations, and it is curious whether the meridional flow itself also shows temporal variations during difference phases of a solar cycle. here we employ a comprehensive time-distance measurement scheme and derive the s... | temporal evolution of solar meridional flow in the deep interior during 2010-2018 |
we present a first observation and analysis of 13.5, 9 and 6.75-day periodic oscillations observed in the neutral mesosphere density in the declining phase of solar cycle 23 and 24. mesospheric densities near 90 km are derived using data from the davis meteor radar (68.5°s, 77.9°e), antarctica. spectral analysis indica... | first observation of mesosphere response to the geomagnetic forcing |
geomagnetic storms can cause irregularities in the ionospheric electron density, which can affect gnss positioning and even cause signal's scintillations. the first order ionospheric effect can be eliminated through an ionosphere-free solution, but higher order terms remain and may cause artificial coordinate variation... | impact of geomagnetic storms and ionospheric disturbances on mid-latitude station's coordinates using static and kinematic ppp |
in the south of the siberian platform (sp) neoproterozoic glacial deposits attributed to the hypothetical snowball event are well-known. these deposits are combined in the middle-siberian glacial horizon (msgh), overlaying conformally by dal'naya taiga group. the latter contain ediacaran acanthomorphids and have a pron... | first evidence of low latitude neoproterozoic glacial deposits containing varves from siberia and their isotopic characteristics |
it is thought that the longer-term variations of the solar activity may affect the earth’s climate. therefore, predicting the next solar cycle is crucial for the forecast of the “solar-terrestrial environment”. to build prediction schemes for the next solar cycle is a key for the long-term space weather study. recently... | predicting solar cycle 25 using surface flux transport model |
we study the solar-cycle variations of the meridional flows near the base of the convection zone to probe the solar-cycle variations of magnetic fields. using soho/mdi data, we measure the acoustic travel-time difference on the meridional plane for different latitudes and different travel distances over 15 years, inclu... | probing magnetic fields near the base of the convection zone with meridional flows |
the ionosphere is a highly complex plasma containing electron density structures with a wide range of spatial scale sizes. large-scale structures with horizontal extents of tens to hundreds of km exhibit variation with time of day, season, solar cycle, geomagnetic activity, solar wind conditions, and location. whilst t... | modelling large-scale structures in the high-latitude ionosphere |
direct spacecraft measurements of the solar wind and heliospheric magnetic field have been performed near-continuously for the over 60 years. the solar wind is seen to vary over all observed time scales, from sub-seconds to decades, with strong evidence of secular trends. in order to fully assess the longer-term variat... | the evolution of the heliosphere over decades, centuries and millennia |
we present principal components analysis (pca) of temporal magnetic field variations over the solar cycles 21-24. these pcs reveal two main magnetic waves with close frequencies (covering 40% of data variance) travelling from the opposite hemispheres with an increasing phase shift. extrapolation of these pcs through th... | two dynamo waves derived with principal component analysis of solar magnetic field and prediction of solar activity on millenium scales |
background: short-term geomagnetic disturbances (gmd) driven by the quasi-periodic 11-year cycle of solar activity have been linked to a broad range of adverse health effects, including cardiovascular diseases (cvd) and total deaths. we conducted a large epidemiological study in 263 u.s. cities to assess the effects of... | geomagnetic disturbances driven by solar activity enhance total and cardiovascular mortality risk in 263 u.s. cities |
it has been noticed recently that the eia in the brazilian eastern, middle, and western sectors present significant longitudinal variability within a short separation due to the presence of typical magnetic field structure over south america (dias et al., 2019). therefore, the main motivation of this study is to invest... | day-to-day variability of the equatorial ionization anomaly (eia) over the brazilian sector using gnss-tec network during the descending phase of the solar cycle 24 |
it is believed that the longer-term variations of the solar activity can affect the earth's climate. therefore, predicting the next solar cycle is crucial for the forecast of the "solar-terrestrial environment". to build prediction schemes for the activity level of the next solar cycle is a key for the long-term space ... | project for solar-terrestrial environment prediction (pstep): towards predicting next solar cycle |
variations in the solar magnetic-field ratio over 13 years are analyzed, relying on the comparison of simultaneous measurements in two spectral lines at the mount wilson observatory (mwo). the ratio and correlation coefficient are calculated over the general working range of measured magnetic-field values and in variou... | variations in ratio and correlation of solar magnetic fields in the fe i 525.02 nm and na i 589.59 nm lines according to mount wilson measurements during 2000 - 2012 |
a study of variations of solar spectral irradiance (ssi) in the wavelength ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. we used various data for ultraviolet (uv) spectral lines and international sunspot number (issn) from interactive data centers as sme (nssdc), uars (gdaac), sorce (lisird) and sidc,... | the variability of solar spectral irradiance and solar surface indices through the solar activity cycles 21-23 |
the results of measurements of telluric currents flowing through pipelines laid in the cryolithozone in yakutia are presented during geomagnetic storms and lightning discharges occurring in the 10 km zone around the pipeline. the currents reach tens of amperes. construction of a lightning density distribution map. the ... | effect of the electromagnetic environment in pipes in yakutia |
subsurface flows vary during the course of a solar cycle showing bands of faster- and slower-than-average rotation and bands of converging meridional flow. these flow patterns migrate with latitude; they first appear during the declining phase of a solar cycle and are present during cycle minimum. they appear several y... | are subsurface flows evidence of hidden magnetic flux during cycle minimum? |
the variability of the solar white-light corona and its connection to the solar activity has been studied for more than a half century. it is widely accepted that the temporal variation of the total radiance of the k-corona follows the solar cycle pattern (e.g., correlated with sunspot number). however, the origin of t... | 3d distribution of the coronal electron density and its evolution with solar cycle |
solar modulation potential (smp) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behavior of the open solar magnetic field over the holocene period. using the greenland ice core project (grip) ^{10}be and intcal13 ^... | on the current solar magnetic activity using its behavior during the holocene |
the variability of the solar white-light corona and its connection to the solar activity has been studied for more than a half century. it is widely accepted that the temporal variation of the total radiance of the k-corona follows the solar cycle pattern (e.g., correlated with sunspot number). however, the origin of t... | evolution of 3d electron density of the solar corona from the minimum to maximum of solar cycle 24 |
in this work we investigate the response of the low latitude ionosphere to recurrent geomagnetic activity caused by events of high speed streams (hsss)/corotating interaction regions (cirs) during the low descending phase of solar activity in the solar cycle 24. intense magnetic field regions called corotating interact... | ionospheric response to a recurrent magnetic storm during an event of high speed stream in october 2016. |
we study the solar-cycle variation of the zonal and meridional flow in the near-surface layers of the solar convection zone from the surface to a depth of about 16 mm. we have analyzed dopplergrams obtained with the michelson doppler imager (mdi) onboard the solar and heliospheric observatory (soho), the global oscilla... | solar-cycle variation of subsurface flows during 20 years |
we assess the reaction of the full martian plasma system after the impact of different interplanetary coronal mass ejections (icme) at mars at different levels of solar activity and phases of the solar cycle 23/24. the mars' plasma system behaviour is characterised from the surface of the planet to the bow shock positi... | mars plasma system response to icme transients at different phases of the solar cycle |
solar cycle variations in solar radiation create notable density changes in the martian ionosphere. in addition to this long-term variability, there are numerous short-term and non-recurrent solar events that hit mars which need to be considered, such as interplanetary coronal mass ejections (icmes), co-rotation intera... | martian ionosphere response to solar wind variability during solar minimum |
we show how a mean field solar dynamo model can be used in conjunction with magnetic observations of the sun in order to estimate the large-scale meridional circulation and further extended to predict the 11-yr cycle. our innovative approach rests on variational data assimilation, where the difference between predictio... | estimating the solar meridional flow and predicting the 11-yr cycle using advanced variational data assimilation techniques |
in recent decades we are moving towards the hypothesis that electromagnetic (em) processes inside the solar system (not yet fully understood from a physical point of view), may be linked with the energy released during major geophysical events (energy expressed in magnitude or volcanic explosivity index). this research... | major geophysical events and transitions of heliospheric magnetic field in the beginning, middle and end phase of the maunder solar minima |
our present understanding, from both empirical and semi-empirical models, indicates that the variations in the total solar irradiance (tsi) on time scales of days to the solar cycle are primarily associated with solar surface magnetic activity, which encompasses sunspots, faculae, and the network. in previous work, app... | temporal relations between total solar irradiance and photometric indices during the last two solar cycles. |
recently discovered long-term oscillations of the solar background magnetic field associated with double dynamo waves generated in inner and outer layers of the sun indicate that the solar activity is heading in the next three decades (2019-2055) to a modern grand solar minimum (gsm) similar to maunder one. we discuss ... | upcoming grand solar minimum induced by double solar dynamo and other solar effects on the earth |
the magnetic strength ratio (msr) (the ratio of observable strengths bλ1/bλ2 in the two spectral lines) is a good indicator of the relationship between strong (order of kg) and weak (no more than a few hg) components of solar magnetic fields. many studies have been devoted to explore the spatial and temporal variations... | on the time variation of the magnetic strength ratio for different combinations of spectral lines |
over the last decade, the solar wind has exhibited low densities and magnetic field strengths, representing anomalous states that have never been observed during the space age. the cycle 23-24 solar activity led to the longest solar minimum in more than 80 years and continued into the “mini" solar maximum of cycle 24. ... | scene setting talk on galactic cosmic ray transport in the heliosphere |
the rising concentrations of greenhouse gases (ghgs) are producing the global warming of the lower atmosphere and the cooling of the upper atmosphere (ionosphere) starting from 50 km or so. the cooling effect of ghgs in the upper atmosphere is termed as "greenhouse cooling" which seems due to infrared radiative cooling... | long-term variations of the ionosphere: f2-region in southern hemisphere |
the diurnal variations in daytime airglow emission intensity measurements at three wavelengths oi 777.4 nm, oi 630.0 nm, and oi 557.7 nm made from a low-latitude location, hyderabad (geographic 17.50 n, 78.40 e; 8.90 n mag. lat) in india have been investigated. the intensity patterns showed both symmetric and asymmetri... | effect of equatorial electrodynamics on low-latitude thermosphere as inferred from neutral optical dayglow emission observations |
beginning with may 2006 data, the national solar observatory is providing uncertainty (spatial-variance) maps to accompany its database of magnetic flux synoptic charts. early studies using few selected integral carrington rotation maps have shown the impact of these uncertainty maps on the outcome numerical models of ... | uncertainties associated to near real-time synoptic magnetic maps and implications for solar wind models |
in this paper we present prediction of solar activity for the next three solar cycles and millennium using as a proxy the solar background magnetic field based on principal component analysis. using symbolic regression analysis we present mathematical formulae for the dipole magnetic waves and calculate their summary c... | double dynamo effect on solar activity and the modern grand solar minimum |
the international reference ionosphere (iri) is the internationally recognized model for calculating empirical ionospheric parameters such as plasma density, composition, and temperature. estimates of the topside f-region ion density rely on accurately predicting the peak density and height of the f-layer and describin... | performance of the iri-2012 model in the low- and mid-latitudes: variations with longitude and solar activity |
we present a new model of thermosphere winds in the f region obtained from variations in the altitude of the peak density of the ionosphere (hmf2). the new magnetic meridional neutral thermospheric (mentat) wind model produces magnetic-meridional neutral winds as a function of year, day of year, solar local time, solar... | mentat: a new magnetic meridional neutral wind model for earth's thermosphere |
a fundamental aspect of solar wind formation is where the plasma originates from on the sun. the solar wind originates from 3 types of coronal magnetic field – the continuously open fields that form coronal holes (chs), or from either active region (ar) or quiet sun (qs) at the magnetic open-closed boundary. relating i... | characterizing the in situ observed solar wind originating from differing solar source regions |
the paper presents the results of the analysis of changes solar and geomagnetic activity in 1925 wolf cycles. a forecast of the maximum geomagnetic activity cycle 25 is made. solar activity is presented by sunspot number rz, geomagnetic activity is expressed by the energetic index calculated from the data of the "lviv"... | solar and geomagnetic activity in 19-25 cycles. |
studying the interaction between solar flares and sunspot groups (sgs) is crucial for understanding and predicting solar activity. we examined the distribution, correlation, and flaring rates in the northern and southern hemispheres to reveal the relationship between different classes of soft x-ray (sxr) flares and dif... | evolutionary relationship between sunspot groups and soft x-ray flares over solar cycles 21-25 |
the solar wind extends outward from the solar corona, suffusing interplanetary space with plasma and magnetic fields. while the solar wind has traditionally been designated as either fast or slow based on its velocity, a new study suggests that there maybe a better way to characterize this highly variable plasma flow.c... | screening for the slow solar wind |
in this paper, we have studied the relationship between the monthly variations of solar wind plasma velocity, interplanetary magnetic field (imf) and geomagnetic activity index (ap) during solar cycles 22-24 (1986-2020). the modulation parameter (ζ =v * b) is proportional to the product of solar wind plasma velocity, v... | solar wind plasma variations with interplanetary magnetic field during solar cycles 22-24 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.