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the study of the sun, our nearest star, is making rapid progress, through a combination of a host of new space-based and ground-based observatories coming online and major advances in numerical simulations that incorporate increasingly complex physical mechanisms. i will provide an overview of some recent exciting disc... | toward a better understanding of the solar atmosphere: combining observations and numerical modeling |
alfvenic waves, in addition to electron beams, have been proposed as an important energy transport mechanism in solar flares, capable of delivering energy to both the corona and chromosphere and giving rise to many of the observed features of flares. we present results of hydrodynamic simulations which include a ray tr... | solar flare heating via alfvenic waves propagating down a coronal loop |
coronal heating is a long-standing problem, still unresolved, and understanding it will allow us to comprehend the mechanism of energy transport from the photosphere to the corona. several mechanisms that can contribute to this phenomenon have been suggested. one of them is the alfvén wave turbulence. in this process t... | contribution of uniturbulence to coronal heating in a coronal hole |
the strongest quasi-steady heating in the solar atmosphere from the photosphere through the corona occurs in plage regions. as many chromospheric heating mechanisms have been proposed, important discriminators of the possible mechanisms are the location of the heating and the correlation between the magnetic field prop... | chromospheric heating mechanisms in a plage region constrained by comparison of magnetic field and mg ii h & k flux measurements with theoretical studies |
collisionless plasmas in space often evolve into turbulence by exciting an ensemble of broadband electromagnetic and plasma fluctuations. such dynamics are observed to operate in various space plasmas such as in the solar corona, the solar wind, as well as in the earth and planetary magnetospheres. though nonlinear in ... | peter gary's picture of short-wavelength plasma turbulence |
one of the major theories to explain the heating of the solar corona is that waves carry the required energy from lower layers of the solar atmosphere into the corona where the waves dissipate, thereby heating the plasma. recent observational evidence has demonstrated that waves are ubiquitous in the corona, but a chal... | quantitative evidence for wave heating of the solar corona |
the x1.0 flare on march 29, 2014 was well observed, covering its emission at several wavelengths from the photosphere to the corona. the rhessi spectra images allow us to estimate the temporal variation of the electron spectra using regularized inversion techniques. using this as input for a combined particle accelerat... | a self-consistent combined radiative transfer hydrodynamic and particle acceleration model for the x1.0 class flare on march 29, 2014 |
observational advances with iris have given the ability to observe details of the coronal transition region (tr) with extremely high spatial resolution. spectral lines formed in the tr, in particular, illuminate the dynamics of mass and energy flow between the chromosphere and corona. using a sophisticated hydrodynamic... | modeling chromospheric nanoflares with hydrad |
plasma confined in curved magnetic field are unstable when the plasma beta (= gas pressure / magnetic pressure) exceeds a critical value determined mainly by the loop geometry (~ loop thickness / curvature radius). in tokamak (one type of fusion experiment device), sudden disruption of confined plasma are observed when... | ballooning instability: a possible mechanism for impulsive heating of plasma trapped in a loop |
transverse, non-compressive turbulence (alfven-wave turbulence) is likely an important mechanism for heating the corona and inner heliosphere. turbulent heating relies upon the cascade of fluctuation energy from large scales to small scales, and in alfven-wave turbulence this energy cascade arises from nonlinear intera... | reflection-driven mhd turbulence in the inner heliosphere |
energy release and particle acceleration on the sun is a frequent occurrence associated with a number of different solar phenomenon including but not limited to solar flares, coronal mass ejections and nanoflares. the exact mechanism through which particles are accelerated and energy is released is still not well under... | foxsi-2 observations and coronal heating |
the electron heating of the solar coronal plasma has remained one of the most important problems in solar physics. an explanation of the electron heating rests on the identification of the energy source and appropriate physical mechanisms via which the energy can be channelled to the electrons. our objective here is to... | solar coronal electron heating by short-wavelength dispersive shear alfvén waves |
the extraction of high-temperature regions in active regions (ars) is an important means to help understand the mechanism of coronal heating. the important observational means of high-temperature radiation in ars is the main emission line of fe xviii in the 94 å of the atmospheric imaging assembly. however, the diagnos... | extraction and analysis of coronal high-temperature components based on outlier detection |
coronal jets are small eruptions characterized by a narrow spire and a luminous loop base. extensive studies using euv and x-ray observations have significantly advanced an understanding of their formation. however, questions regarding their heating and acceleration remain. previous yohkoh-era white-light observations ... | investigation of white light jets using mauna loa's k-coronograph |
the energy potential of solar nanoflares is estimated with a new approach proposed by the author. this approach is based on the drift mechanism for the formation of a dense loop structure in the magnetic field of a bipolar source. the densification process is assumed to proceed until the appearance of unmagnetized prot... | formation conditions and energetics of solar nanoflares |
i will examine the dynamics of solar coronal loops containing non-trivial magnetic field line braiding, in the context of parker's braiding mechanism for coronal heating. the existence of braided force-free equilibria will be discussed, including a demonstration that these equilibria must contain current layers whose t... | energy release in braided coronal loops |
the newly renamed, parker solar probe (psp) mission will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed i... | parker solar probe: a nasa mission to touch the sun: mission status update |
two main models have been developed to explain the mechanisms of release, heating, and acceleration of the nascent solar wind, the wave-turbulence-driven (wtd) models and reconnection-loop-opening (rlo) models, in which the plasma release processes are fundamentally different. given that the statistical observational p... | helium abundance and speed difference between helium ions and protons in the solar wind from coronal holes, active regions, and quiet sun |
alfvén waves contribute significantly to the solar coronal heating, the solar wind acceleration, as well as alfvénic turbulence formation. they play a pivotal role during energy release, transport, and dissipation in the solar atmosphere and heliosphere. however, the origin of the alfvén waves in the solar corona remai... | spontaneous generation of alfvén waves during three-dimensional magnetic reconnection in the solar corona |
coronal flare emission is commonly observed to decay on timescales longer than one-dimensional flare loop models typically predict. this discrepancy is most apparent during the gradual phase, where emission from impulsively driven models decays over minutes, in contrast to the hour or more often observed. magnetic reco... | a model for gradual phase heating driven by mhd turbulence in solar flares |
observations of flaring active regions in euv with sdo/aia over more than a decade show ample evidence of quasi-periodic fast (qfp) magnetosonic waves in coronal active regions (ar) associated with pulsating flares. the qfp waves can carry significant energy flux that may contribute to ar heating. recently, we have inv... | modeling flare-driven quasi-periodic fast magnetosonic waves in coronal active regions |
in order to have thermodynamically stable loops, at typical million-degree coronal temperatures, some heating mechanism is necessary to compensate for the energetic loses observed along the loops. in a previous work, we developed a procedure to estimate, using differential emission measure tomography in combination wit... | modelling of quiet-sun coronal loops in thermodynamic equilibrium |
a numerical model describing kinetic alfven waves (aws) turbulence in coronal magnetic structure like coronal loops is presented. the governing equation representing kinetic aws is derived using a two-fluid approach and solved by a pseudospectral method for efficient numerical simulation including effects of density fl... | nonlinear kinetic alfvén-wave localized structures and turbulence generation in the solar corona |
we report here on the first inferences of the fe+9 ion temperature derived from spectroscopic observations of the fe x 637.4nm emission line, over a heliocentric distance range of 1.075-1.368 r⊙ within two polar coronal holes. the observations were conducted during the total solar eclipse of 2019 july 2 at the cerro to... | on the inference of fe+9 ion temperature in the solar corona from the 2019 july 2 total solar eclipse |
the alfven wave turbulence based solar atmosphere model (awsom) employs the turbulent dissipation as the unified mechanism to explain both the coronal heating in the closed field region and powering and accelerating the solar wind in the coronal holes. the pronounced difference in the heating efficiency between the clo... | surface alfven wave reflection as the slow wind formation mechanism in the alfven wave driven solar atmosphere model |
the solar wind is a supersonic plasma flow streamed from the solar corona. the solar wind is classified into the fast wind (typically ~750 km/s) and the slow wind (~300 km/s). the acceleration of the solar wind mainly occurs in the outer corona at heliocentric distances of about 5–20 rs (= solar radii), where the coro... | physical properties of the solar corona derived from radio scintillation observations with the akatsuki spacecraft |
the upper transition region at the footpoints of the hottest loops in active regions is known as moss, highly structured and dynamic 1 mk plasma that is formed at the same heights as dynamic chromospheric jets emanating from the underlying plage regions. moss provides an excellent laboratory to disentangle the complex ... | the correlation between chromospheric and coronal heating in active region plage |
we investigate abundance variations of heavy ions in coronal loops. we develop and exploit a multi-species model of the solar atmosphere (called irap's solar atmospheric model: isam) that solves for the transport of neutral and charged particles from the chromosphere to the corona. we investigate the effect of differen... | simulating the fip effect in coronal loops using a multi-species kinetic-fluid model. |
we investigate the solar coronal heating problems. we aim to model the field-line braiding mechanism with magnetic foot-points that are shuffled to generate an upward poynting flux. the magnetic energy then travels into the corona. these perturbations induce electric currents that later heat the coronal plasma through ... | heating and cooling in an atmospheric model of the solar corona |
interchange reconnection (ir) is a magnetic reconnection scenario occurring at the boundary between open- and closed-field regions of the solar atmosphere, where magnetic connectivity is "interchanged" between the two. ir has been suggested as a mechanism for forming magnetic switchbacks in the solar wind, as have been... | modeling fluid evolution of interchange reconnection aftermath |
kinetic alfvén waves become unstable when the field-aligned drift velocity is larger than the phase velocity of the waves. the unstable wave can grow and play a very important role in the energy transport in solar coronal plasma. in this paper, we consider field-aligned drift and temperature anisotropic velocity distri... | instability and energy transport of kinetic alfvén waves in the solar corona |
in this work we represent the concept of a unique scientific satellite experiment aimed to study the effects due to the influence of the burst component of the solar corona and magnetospheric soft x-ray emission on the spatial and temporal distribution of the high-energy charged particles filling the earth's radiation ... | from solar corona to radiation belts: an idea of joint experiment on one cubesat |
the hot, 1 million k solar corona exists because of a balance between radiative and conductive energy losses and some yet unknown coronal heating mechanism, which remains one of the major puzzles in solar physics. such a thermal equilibrium can be readily perturbed by magnetoacoustic waves which are omnipresent in the ... | a new look at the sun's corona as an active medium: implications for coronal seismology |
the dissipation of magnetized turbulence is an important paradigm for describing heating and energy transfer in astrophysical environments such as the solar corona and wind; however, the specific collisionless processes responsible for heating remain relatively unconstrained by measurements. observations of particle di... | signatures of wave-particle resonant interactions using an orthonormal hermite basis |
turbulence in plasmas involves a complex cross-scale coupling of fields and distortions of particle velocity distributions, with the generation of non-thermal features. how the energy contained in the large-scale fluctuations cascades all the way down to the kinetic scales, and how such turbulence interacts with partic... | turbulence evolution of coronal hole solar wind in the inner heliosphere: solar orbiter and parker solar probe combined observations |
radio observations are excellent probes of supra-thermal charges and magnetic fields in the coronae/magnetospheres of the coldest stars and brown dwarfs, and they are vital for identifying the impact of stellar plasma on exoplanet atmospheres and the coronal heating mechanism. their strong magnetic field leads to radio... | radio-emitting engines in m dwarfs |
in the solar wind near the sun, enhanced density fluctuations are reported by both in-situ and remote sensing observations, indicating the importance of compressible turbulence. but the generation mechanism for the density fluctuations in the solar wind is still under debate. in this study, we use a 3d compressible mhd... | simulating compressible turbulence in near-sun solar wind |
the acceleration of the solar wind mainly occurs in the outer corona at heliocentric distances of about 5-20 r_{s} (= solar radii), where the coronal heating by magnetohydrodynamic waves and the wave-induced magnetic pressure are thought to play major roles in the acceleration. the mechanisms have not been fully confir... | physical properties of the inner solar corona derived from radio scintillation observations with the akatsuki spacecraft |
axions from the local dark matter halo of the galaxy convert infrared light emerging from the surface of the sun into radio waves that resonate with the cyclotron motion of electrons within coronal loops. dark matter-driven electron cyclotron resonance heating of the coronal plasma works best in times and places where ... | dark matter heats crown, cools spots, and drives wind |
ion heating, including protons, alpha particles and minor ion species, is being explored in pic simulations of 3d magnetic reconnection with applications to impulsive flares. reconnection in 3d configurations with an ambient guide field become turbulent as multiple x-lines develop and drive alfvenic flows. such turbule... | ion acceleration and the development of turbulence during 3d magnetic reconnection in impulsive flares |
turbulence is a ubiquitous and fundamental process in plasmas throughout the universe, from galaxy clusters to the solar corona and tabletop laboratory experiments. turbulence gives rise to a cascade of energy from large to small scales, where a variety of dissipation mechanisms become active and dissipate the electrom... | dissipation of plasma turbulence: linear vs non-linear processes, reduced kinetic models, and field-particle correlations (scene-setting) |
the development of a detailed understanding of turbulence in magnetized plasmas has been a long standing goal of the broader scientific community, both as a fundamental physics process and because of its applicability to a wide variety of phenomena. turbulence in a magnetized plasma is the primary mechanism responsible... | a vlasov-maxwell study of phase space dynamics of turbulence |
velocity distribution functions of plasma particles measured by spacecraft in the solar wind generally show non-thermal features, and especially the presence of enhanced suprathermal tails. such distributions can well be fitted by different kinds of velocity distribution functions, such as a sum of two (bi-)maxwellians... | non-thermal velocity distributions in the solar wind |
one of the greatest conundrums we have in modern spacecraft missions is the fact that instruments are capable of taking high-resolution full burst-mode data 24 hours a day, but due to telemetry limitations between the spacecraft and earth, the poor bandwidth can only afford to downlink a few minutes of it. if we know a... | resolving velocity-space signatures of particle energization mechanisms onboard modern spacecraft |
magnetic reconnection has been recognized as one of the key mechanisms for heating and bulk acceleration of space plasmas. to date, many observations have been made on the solar corona to confirm the presence of high-temperature and high-speed plasma flows produced by magnetic reconnection above flare arcades. in this ... | magnetic reconnection in the solar atmosphere: future plans for reconnection observations |
as space plasmas are highly collisionless and involve several temporal and spatial scales, understanding the physical mechanisms responsible for energy and mass transport between these scales is a challenge. in this review talk i discuss the role of the velocity shear -driven kelvin-helmholtz (kh) instability (khi) on ... | role of kelvin-helmholtz instability on the plasma transport and heating in the heliosphere |
the presence of heavy ions has a profound impact on the temporal response of the magnetosphere to internal and external forcing, and plays a key role in plasma entry and transport processes within the terrestrial magnetosphere.numerous studies focused on the transport and energization of o+ through the ionosphere-magne... | tracking the differential transport and acceleration of nitrogen and oxygen ions from the terrestrial ionosphere to the inner magnetosphere |
the solar wind flow is a key component of space weather, being the source of corotating density structures that perturb planetary atmospheres and affecting the propagation of impulsive perturbations (such as cme). wind streams with different properties (speed, density, composition, waves) develop at different locations... | charting new solar territories: fair winds for parker solar probe and solar orbiter |
solar flares are driven by the release of magnetic energy from reconnection events in the solar corona, whereafter energy is transported to the chromosphere, heating the plasma and causing the characteristic radiative losses. in the collisional thick-target model, electrons accelerated to energies exceeding 10 kev trav... | science objective: understanding energy transport by alfvénic waves in solar flares |
while the origin of the solar wind is still an open problem, observations indicate that fast, and sometimes slow, wind originates from equatorial coronal holes. however, the exact locations within them, and the mechanisms that cause the heating and outward acceleration of solar plasmas, are not understood. in the prese... | the relation between plasma properties and uv intensity fluctuations in equatorial coronal holes |
stochastic heating, a non-linear heating mechanism driven by the violation of magnetic moment invariance due to large-amplitude turbulent fluctuations producing energy diffusion perpendicular to the magnetic field, is frequently invoked as a mechanism responsible for the heating of ions in the solar wind. here, we quan... | stochastic heating of the solar wind becomes increasingly significant close to the alfven critical point |
quasi-periodic density fluctuations appear ubiquitous in the regions where the solar wind forms and accelerates. the origin of these fluctuations is still debated and could result from a number of physical processes including rising mhd waves, periodic impulsive heating or continual magnetic reconnection. the recent an... | origins of density fluctuations in the solar corona explored with time-dependent mhd simulations |
solar coronal heating is a nonlinear quantum mechanical phenomenon. corona is a powerful source of x-rays and ionisations & emissions of such radiations are quantum mechanical and levels are highly unstable to order of femto-seconds. a linear method of energy transfer like collisional ionisation to such levels is p... | solar coronal heating by gravity-induced resonant emission |
recent progress in observations of solar wind turbulence dissipation and kinetics has focused on intermittent structures, kinetic alfven waves, and whistler waves. this presentation will review the literature and present recent results showcasing cyclotron emission from unstable distributions and cyclotron absorption o... | who cares about cyclotron damping? |
several recent observational analyses have shown that plasma heating enters into the energy budget of coronal mass ejections (cmes) at about the same order of magnitude as the kinetic energy. the ultimate source of the heating is the magnetic field, but the mechanisms by which magnetic energy is converted to thermal en... | plasma heating during coronal mass ejections |
in the earth's magnetosphere the specific entropy, increases by approximately two orders of magnitude when transitioning from the magnetosheath into the magnetosphere. however, the origin of this non-adiabatic heating is not well understood. in addition, there exists a dawn-dusk temperature asymmetry in the flanks of t... | on the magnetospheric heating problem |
the solar corona, the outer atmosphere of the sun, is 200 times hotter than the underlying visible surface of the sun. recent coronal observations find alfvén wave damping at unexpectedly low heights in the corona, suggesting that alfvén waves may contribute to the heating of the corona to temperatures of 106 k. dissip... | exploring the role of alfvén waves in heating the solar corona |
observations indicate that the solar wind results from strong heating of coronal ions, primarily in the directions perpendicular to the large-scale magnetic field. this heating is thought to be caused by turbulent dissipation of alfvén wave energy, though the kinetic details of the dissipation are yet not known. an und... | quasilinear consequences of perpendicular turbulent ion heating |
the resonant ion heating by high-frequency alfven waves is believed for long time to be the primary dissipation mechanism for solar coronal heating, and these high-frequency alfven waves are considered to be generated via cascade from low-frequency alfven waves. in this study, we report an unusual harmonic alfven event... | in situ observations of harmonic alfven waves and associated heavy ion heating. |
one of the three overarching science objectives of parker solar probe is tracking energy in the near-sun environment as it heats the solar corona and accelerates the solar wind. our current understanding, informed by remote observations and theoretical considerations, is that different energization processes may be dom... | tracking energization and dissipation in the near-sun environment with parker solar probe |
the physical mechanisms at play during the formation of the solar wind are still debated however they have a great impact on large scale flows. we propose a new model to study the origin of the solar wind extending from the chromosphere through the transition region into the corona. the model solves a set of 1-d conser... | simulating ion charge states in the solar wind using a multi-species coronal model |
a new mechanism for abundance enhancements of high-energy helium-3 produced by impulsive flares is explored. observations have shown a 103-104 increase in the high-energy helium-3 abundance following impulsive solar flares. a likely mechanism is the resonant heating of helium-3 in the corona by alfvén-cyclotron waves. ... | a mechanism for helium-3 abundance enhancements in solar flares |
the transport of energy in the solar wind is a complicated process where competing mechanisms transfer energy back and forth between the charged particles that make up the plasma and the electric and magnetic fields that are generated by their motion. at small scales, microinstabilities driven by non-equilibrium featur... | free energy available to microinstabilities in the solar wind |
alfven waves (aw's) and aw turbulence play an important role in several models for the heating of the solar corona and the acceleration of solar wind. in the heating scenario, the role of aw's is to transport energy from convective motions on the photosphere into the solar atmosphere, corona, and solar wind, where as t... | comparing parker solar probe observations with theory and simulations of reflection-driven alfven turbulence |
emission lines from the 100,000 k solar transition region are generally red-shifted and broadened beyond what can be attributed to their temperature. the reason for either remains unclear at this time. we use observations of the si iv1402.77a line in quiescent active regions, made by iris, to show that the doppler shif... | implications of the correlation between doppler shifts and line widths in si iv spectral lines from the active region transition region |
i will present a new series of solar wind simulations of the solar wind from the surface of the sun to 1 au (and beyond). we used a new solar wind model, called multi-vp, which takes a coronal magnetic field map as input (past data or forecast) and calculates the dynamical and thermal properties of a large collection o... | modeling the solar wind from 1 rsun to 1 au |
several applications of the inhomogeneity generated waves are discussed in the solar (coronal heating, reconnection, flare particle energization, etc.) and magnetospheric physics. while many acceleration and heating mechanisms | inhomogeneity generated wave physics in magnetic reconnection, electron and ion heating and acceleration, and solar particle energization |
solar-c euvst (euv high-throughput spectroscopic telescope) is designed to comprehensively understand the energy and mass transfer from the solar surface to the solar corona and interplanetary space, and to investigate the elementary processes that take place universally in cosmic plasmas. the proposed mission is a fun... | science objectives of the solar-c_euvst |
plasma turbulence is a widespread phenomenon in our universe, such as in the solar wind, solar corona, and black hole accretion disks. understanding how turbulent energy is transferred from large to small scales and is eventually dissipated into plasma heat, or some other form of particle energization, is a grand chall... | implementation of field-particle correlation technique onboard spacecraft: parker solar probe and beyond |
turbulent magnetic relaxation is an important candidate mechanism for coronal heating and some types of solar flare. by developing turbulence that reconnects the magnetic field throughout a large volume, magnetic fields can spontaneously self-organize into simpler lower-energy configurations. we are using resistive mhd... | revisiting taylor relaxation |
a long-lasting problem in solar physics is that how the plasma is heated to several million kelvins in the solar corona. several different mechanisms have been proposed, including alfven wave dissipation and magnetic reconnection (nano-flares). both of them are capable of providing the required power, in generic circum... | observationally quantified reconnection providing a viable mechanism for active region coronal heating |
i will present a set of accurate simulations of the background solar wind from the surface of the sun up to 1 au (and beyond), and of cme propagation through the heliosphere covering a time interval between 2007 and 2017. these simulations were performed in the scope of the helcats fp7 project and are the base of its s... | simulating and cataloguing the solar wind |
the region of space dominated by the sun's magnetic field is called the heliosphere. it envelops the entire solar system including earth. therefore, a strong coupling exists between the sun and our planet. the sun continuously ejects particles, the solar wind, and when these high energy particles hit earth, the magneto... | o+ outflow during geomagnetic storms observed by cluster satellites |
solar wind temperature at 1 au exhibits statistical correlation with the magnetic structure, wherein regions with high temperature are found to be associated with coherent structures [1]. using parker solar probe (psp) data from the first encounter, we studied this correlation between the magnetic field structure, meas... | intermittent heating in the inner heliosphere: psp observations |
van allen probes studies have demonstrated that electrons up to energies over 10 megaelectron volts (mev) can be produced over broad regions of the outer van allen zone on timescales of minutes to a few hours. the key to such rapid acceleration is the interaction of "seed" populations of 10 to 200 kev electrons (and su... | radiation belt acceleration and loss: forecasting solar wind driving effects |
there are many bright soft x-ray (sxr) loops above active regions on the sun. we don't fully understand the heating mechanisms of the loops yet.in order to obtain the information of the initial heat-up of the coronal loops, we study x-ray bright points (xbps) above emerging flux regions (efrs) in early phase.first we i... | x-ray bright points above emerging flux regions |
we are interested in examining computationally the relation between cmes and flares in the solar regime. for that, two cutting-edge numerical codes are recruited, bats-r-us on the magnetohydrodynamic end and (implicit) ipic on the kinetic end. a two way coupling between the two codes has been implemented in order to ex... | self-consistent multi-scale physics 3d cme-flare modeling |
venus and earth are similar in terms of size and bulk composition, yet their surface conditions are radically different. earth has hosted plate tectonics and a global magnetic field for billions of years, sustaining water oceans and allowing life to flourish. a thick atmosphere chiefly composed of carbon dioxide, in co... | the divergent evolution of earth and venus |
a new physical mechanism to accelerate 3he ions with radiofrequency (rf) waves in plasmas composed of mainly h and d has recently been theoretically predicted and experimentally proven in magnetic fusion devices [1]. this 'three-ion heating scenario' allows for a very efficient power transfer from the ion cyclotron wav... | a novel and efficient technique for generating energetic 3he ions in multi-ion plasmas:a possible mechanism for enrichment of 3he in solar flares? |
the transport of matter and radiation in the solar wind and terrestrial magnetosphere is a complicated problem involving competing processes of charged particles interacting with electric and magnetic fields. given the rapid expansion of the solar wind, it would be expected that superthermal electrons originating in th... | magnetic pumping of the solar wind |
scaling properties of the stochastic component of euv intensity fluctuations from aia/sdo observations show long-term correlations and can carry information about the energetics of coronal loops. power spectra indicate that the stochastic time series are nonstationary. thus we apply the method of detrended fluctuation ... | scaling and long term correlation properties of euv intensity fluctuations and implications for impulsive heating mechanisms of the solar corona |
recent solar observations suggest that the sun's corona is heated by alfven waves that dissipate at unexpectedly low heights in the corona. these observations raise a number of questions. among them are the problems of accurately quantifying the energy flux of the waves and that of describing the physical mechanism tha... | understanding solar coronal heating through atomic and plasma physics experiments |
abstract supra-arcade downflows (sads) are elongated features usually observed above post-eruption flare arcades, with low emission, low density, and high temperature. although sads have been observed and studied extensively, their physical interpretation and mechanism remain not well understood and controversial. in o... | numerical modeling of supra-arcade downflows |
the mechanism of the solar corona heating still remains unexplained, almost 80 years after the discovery of the million degree hot solar corona. observations show that the temperature increases more than one order of magnitude in the transition region (tr), the boundary between the solar chromosphere and the solar coro... | temperature and wind profiles of the solar transition region - preliminary results |
shocks in the interplanetary medium ahead of coronal mass ejections (cmes) can accelerate solar wind plasma to high energies. ions heavier than protons can be used as tracers for the associated heating and acceleration mechanisms in the solar wind plasma. parker solar probe (psp) will be able to measure these shocks ve... | understanding heliospheric shock evolution using parker solar probe |
parker solar probe (psp) will make the first in situ measurements of the near-sun environment, a region of the inner heliosphere in which a number of different heating and energization mechanisms have been proposed to act. one method for distinguishing between heating mechanisms is to measure the velocity-space structu... | numerical preparations toward identifying heating mechanisms using distributions function measurements from sweap and parker solar probe. |
we study how different heating and acceleration processes of stellar winds affect their mass-loss rates and the conditions near exo-planets at close distances of 10 stellar radii. the exact mechanisms responsible for the heating and acceleration of the solar wind are still being debated. we explore thermal heating (coh... | the effect of the heating and acceleration of winds on conditions ahead of hot jupiters: solar and v374 peg cases |
coronal mass ejections (cmes) are some of the largest, most energetic events in the solar system releasing an immense amount of plasma and magnetic field into the heliosphere. the earth-bound plasma plays a large role in space weather, causing geomagnetic storms that can damage space and ground based instrumentation. a... | empirical modeling of icmes using ace/swics ionic distributions |
solar flares are the result of a rapid release of magnetic energy stored in the solar corona. an ideal-mhd process, such as a loss of magnetic equilibrium, most likely initiates the flare, but the non-ideal process of magnetic reconnection quickly becomes the dominant mechanism by which energy is released. within the l... | magnetic energy release in solar flares |
what is the pre-cursor of a solar eruption is a key question in solar physics for both understanding the physical mechanism and predicting solar eruptions. in this letter, we present the finding of flux rope oscillation as well as significant plasma heating before the onset of an x1.6 goes x-ray flare and the eruption ... | observations of magnetic flux-rope oscillation during the precursor phase of a solar eruption |
we investigate coronal heating properties in active region cores in non-flaring conditions, using high spatial, spectral, and temporal resolution chromospheric/transition region/coronal observations coupled with detailed modeling. we will focus, in particular, on observations with the interface region imaging spectrogr... | constraints on active region coronal heating properties from observations and modeling of chromospheric, transition region, and coronal emission |
turbulence cascade transfers energy from large scale to small scale but what happens once kinetic scales are reached? in a collisional medium, viscosity and resistivity remove fluctuation energy in favor of heat. in the weakly collisional solar wind, (or corona, m-sheath, etc.), the sequence of events must be different... | how plasmas dissipate: cascade and the production of internal energy and entropy in weakly collisional plasma turbulence |
one important clue to the physical mechanism of chromospheric heating in the sun is provided by the well-known widespread presence of chromospheres in most cool stars. recent uv observations are shedding more light into the characteristics of these chromospheres and transition-regions. the physical modeling of these, c... | chromospheres of various cool stars from models of the uv |
small-scale plasmoid releases from the sun's helmet streamers have been widely observed in large-angle and spectrometric coronagraph (lasco) c2 and c3 images of the solar corona. this dynamic process is thought to be linked to the slow solar wind. to date, the formation and release mechanism of these blobs have not bee... | 3d simulation of periodic release of plasmoids from helmet streamers |
the miniature x-ray solar spectrometer (minxss) is a 3u cubesat with deployment from the iss planned in q2 2016. its goal is to measure the solar soft x-ray (sxr) spectral irradiance, an observational signature of hot plasma in the solar corona. over the last few decades, there have been very few spectrally resolved ob... | science goals and first light analysis from the miniature x-ray solar spectrometer (minxss) cubesat |
aiming at better understanding the mechanism(s) responsible for the coronal heating we focus on analyzing the properties of the magnetically generated small-scale heating events (sshes) in the solar atmosphere. we present a comprehensive method to detect and follow sshes over time in 3d-mhd simulations of the solar atm... | detection and characterization of small-scale heating events in the solar atmosphere from 3d-mhd simulations and their potential role in coronal heating |
aiming at better understanding the mechanism(s) responsible for the coronal heating and the ubiquitous redshifts observed in the lower transition region we focus on analyzing the properties of small-scale heating events (sshes) in the solar atmosphere. we present a comprehensive method to follow sshes over time in 3d-m... | characterization of small-scale heating events in the solar atmosphere from 3d-mhd simulations and their potential role in coronal heating |
coronal jets are transient, collimated eruptions that occur in regions of open or semi-open magnetic fields in the solar corona. our understanding of these events has significantly improved in recent years, owing to improved observational capabilities and numerical simulations. yet, several important questions concerni... | modeling jets in the corona and solar wind |
a multitude of mhd waves have been observed at a large range of scales in the solar atmosphere. according to theories and models, transverse (or "alfvénic") waves are a viable mechanism for both heating and accelerating the solar wind and may also drive certain elemental fractionation processes in the chromosphere and ... | automating direct observations of transverse waves in the solar corona |
measurements of the electron velocity distribution function ( evdf ) in the solar wind routinely detect a narrow, magnetic-field-aligned population of suprathermal runaway electrons, termed the " strahl ." due to its high energy and strong anisotropy, the strahl provides a significant contribution to the field-parallel... | non-maxwellian electrons in the solar wind: their origin and their role |
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