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the nearly right unitarity triangle can be simply obtained if a quark mass matrix is written as a linear combination of real rank-1 matrices and the coefficient which gives the mass of the second generation is pure imaginary. supposing that the source of the cp violation is in the yukawa coupling to an additional higgs... | nearly right unitarity triangle and cp phase in quark and lepton flavor mixings |
we study the phenomenological implications of two minor zeros in neutrino mass matrix using trimaximal mixing matrix. in this context, we analyse fifteen possible cases of two minor zeros in neutrino mass matrix and found only two cases, namely class $a_1$ and class $a_2$, that are compatible with the present neutrino ... | phenomenological study of two minor zeros in neutrino mass matrix using trimaximal mixing |
the time–energy uncertainty relation (teur) plays a fundamental role in quantum mechanics, as it allows the grasping of peculiar aspects of a variety of phenomena based on very general principles and symmetries of the theory. using the mandelstam–tamm method, teur has recently been derived for neutrino oscillations by ... | time–energy uncertainty relation for neutrino oscillations: historical development, applications, and future prospects |
we propose a model with $a_4$ flavor symmetry for leptons and quarks in the framework of supersymmetric su(5) grand unified theory (gut). the running masses of quarks and charged leptons at gut scale ($\sim 10^{16}$ gev) are realized by the adjoint 24-dimensional higgs multiplet and additional gauge singlet scalar fiel... | $a_4$ flavor symmetric model in susy su(5) gut |
this chapter discusses three nucleosynthesis processes involved in producing heavy nuclei beyond the iron group that are influenced or shaped by neutrino interactions: the v process, the vp process and the r process. these processes are all related to explosive events involving compact objects, such as core-collapse su... | neutrinos and heavy element nucleosynthesis |
neutrino oscillation phenomenon is a definite evidence of physics beyond the standard model (sm) and high precision measurement of neutrino properties will certainly give us clue about what lies beyond the sm. in particular, precise measurements of the mixing matrix elements $u_{\alpha i}$ which relate the neutrino fla... | new physics in neutrino oscillation: nonunitarity or nonorthogonality? |
we present a unified model without the need for an ad hoc standard model hypothesis; we explain why there are three generations of charged and neutral leptons, why neutrinos have a vanishingly small mass, and why flavor-mixing emerges and mass oscillations occur. we show that the sedenion algebra contains three types o... | a unified sedenion model for the origins of three generations of charged and neutral leptons, flavor mixing, mass oscillations and small masses of neutrinos |
we study the propagation of neutrinos from compact astrophysical objects with strong magnetic field, such as magnetars. both neutrino spin rotation and oscillations in a realistic three-flavor model are taken into account. we solve the neutrino evolution equation in the magnetic field near the object and obtain the pro... | spin rotation of neutrinos produced by compact magnetized astrophysical objects |
accelerator based neutrino oscillation experiments seek to measure the relative number of electron and muon neutrinos and antineutrinos at different $l/e$ values. however high statistics studies of neutrino interactions are almost exclusively measured using muon neutrinos and antineutrinos since the dominant flavor of ... | measurement of electron neutrino and antineutrino cross sections at low momentum transfer |
standard three-flavor neutrino oscillations have well explained by a wide range of neutrino experiments. however, the anomalous results, such as electron-antineutrino excess seen by lsnd and miniboone do not fit the three-flavor paradigm. this can be explained by an additional fourth flavor sterile neutrino at a larger... | nova short-baseline tau neutrino appearance search |
the phenomena of neutrino oscillations can proceed only in the case of the coherent superposition of neutrino mass states. an external environment can modify a neutrino evolution in a way that conditions for the coherent superposition of neutrino mass states are violated. such a violation results in quantum decoherence... | neutrino decoherence in matter |
an accurate prediction of the geo-neutrino signal from the crust serves as a necessary prerequisite in the determination of the geo-neutrino flux from the mantle. in this work we report the non-negligible effect associated to the exact three-flavor antineutrino survival probability in the calculation of the crustal geo... | non-negligible oscillation effects in the crustal geo-neutrino calculations |
it is proposed that the energy-momentum expectation values of flavor states should be identified with the missing energy-momentum of neutrino processes so that the conservation of energy-momentum can be strictly imposed. it is also observed that there is a plausible condition to express neutrino mixing angles in terms ... | neutrino oscillations and energy-momentum conservation |
this letter proposes an alternative quantum mechanical picture for the observed phenomena of neutrino oscillations. it is assumed in the following that neutrinos interact via diabatic (or localised) interactions with a new particle field, which changes their flavor. furthermore, it is assumed that each neutrino flavor ... | reinterpreting neutrino oscillations |
among the information provided by high energy neutrinos, a promising possibility is to analyze the effects of a violation of equivalence principle (vep) on neutrino oscillations. we analyze the icecube data on atmospheric neutrino fluxes under the assumption of a vep and obtain updated constraints on the parameter spac... | icecube constraints on violation of equivalence principle |
neutrino oscillation physics has entered a new precision era, which poses major challenges to the level of control and diagnostics of the neutrino beams. in this paper, we review the design of high-precision beams, their current limitations, and the latest techniques envisaged to overcome such limits. we put emphasis o... | design and diagnostics of high-precision accelerator neutrino beams |
we have considered a model, originally proposed by ma and wegman, where the mixing pattern in neutrino sector is explained with three higgs doublets, six higgs triplets and $a_4$ symmetry. the mixing pattern is explained with the help of vacuum expectation values (vevs) of the above mentioned doublets and triplets. in ... | analyses of scalar potential and lepton flavor violating decays in a model with $a_4$ symmetry |
we demonstrate that in the presence of (pseudo)scalar four-fermion nonstandard interactions, a homogeneous and isotropic gas of majorana neutrinos placed in a strong magnetic field can exhibit an angular flavor instability mixing the two neutrino helicities (i.e., a `neutrino-antineutrino' instability). this instabilit... | angular instabilities of a homogeneous neutrino gas from (pseudo)scalar nonstandard self-interactions |
in this paper, we discuss neutrino mass eigenvalues for four flavor neutrino mixing. an extra mass states, in four flavor mixing and possible various combination of cp violating majorana phases effects the neutrino mass eigenvalues. we have considered the effective majorana mass m_{e}, related for \,\left(\beta\beta\ri... | neutrino mass eigenvalues for different scheme within four flavor neutrino framework |
the theory of neutrino oscillation predicts that if both neutrino and antineutrino coming from z0 decay are detected, one can observe an oscillation pattern between the corresponding detectors. this prediction is based on two properties; the neutrino-antineutrino pairs are produced coherently and they are detected with... | mixed states for neutral current neutrino oscillation |
we explore an anomaly-free u (1) gauge extended beyond the standard model (bsm) framework, to account for the baryon asymmetry of the universe, along with arranging for tiny neutrino mass. neutrino masses are generated via higher-dimensional operators (hdos) involving three right-handed neutrinos (rhns) with gauge char... | leptogenesis in an anomaly-free u(1) extension with higher-dimensional operators |
leptonic mixing patterns are usually extracted on the basis of groups or algebraic structures. in this paper, we introduce an alternative geometric method to study the correlations between the leptonic mixing parameters. at the 3$\sigma$ level of the recent global fit data of neutrino oscillations, the distribution of ... | the geometric correlations of leptonic mixing parameters |
we present a low-scale type-i seesaw scenario with discrete flavor and cp symmetries. this scenario not only explains the measured values of the lepton mixing angles, but also makes predictions for leptonic cp violation, and connects the low-energy cp phases relevant for neutrino oscillation and neutrinoless double bet... | interplay between resonant leptogenesis, neutrinoless double beta decay and collider signals in a model with flavor and cp symmetries |
we consider a tev scale resonant lepogenesis within type-i seesaw mechanism. we show that a concrete model based on $a_4$ flavor symmetry with a scaling ansatz in the neutrino dirac mass matrix and a retro-circulant heavy majorana mass matrix can be realized. the full yukawa coupling matrix $y_{\nu}$ can be fully recon... | $tev$-scale resonant leptogenesis $a_4$ with a scaling texture |
grbs are the most energetic electromagnetic events in the universe. those whose typical duration is longer than a few seconds are known as long grbs and shorter than a few seconds are short grbs. it is widely accepted that these events are associated with the collapse of a very massive star and the neutron star (ns) bi... | unraveling the nature of grbs progenitors though neutrinos |
with the help of a block parametrization of the canonical seesaw flavor textures in terms of the euler-like rotation angles and cp-violating phases, we derive a general and explicit expression for the jarlskog invariant of cp violation in neutrino oscillations and compare it with the cp-violating asymmetries of heavy m... | cp violation in light neutrino oscillations and heavy neutrino decays: a general and explicit seesaw-bridged correlation |
in this paper, we study the effect of the minimal length on neutrino oscillation in a static magnetic field. in the framework of the generalized uncertainty principle, we reformulate the hamiltonian for a relativistic neutrino moving in a magnetic field oriented along the z-direction of cartesian coordinates. using the... | effect of minimal length uncertainty on neutrino oscillation |
we propose an extended 2hdm with $q_6\times z_4\times z_2$ symmetry that can interpret the sm fermion mass hierarchy and their mixing patterns with the dirac cp phase in the framework of the type-i seesaw mechanism. the smallness of neutrino masses is obtained via the type-i seesaw mechanism. both normal and inverted n... | fermion masses and mixings, fcncs and $g-2$ muon anomaly in an extended 2hdm with $q_6$ flavor symmetry |
data from several neutrino experiments suggest an anomalous neutrino flavor transition across relatively short baselines which is in conflict with the three-flavor neutrino oscillation paradigm. in particular, miniboone and best collaborations have reported anomalous findings at $\sim 5\sigma$. in this contribution, su... | short baseline oscillations and the gallium mystery |
results from experiments like lsnd and miniboone hint towards the possible presence of an extra ev scale sterile neutrino. the addition of such a neutrino will significantly impact the standard three flavor neutrino oscillations. in particular, it can give rise to additional degeneracies due to additional sterile param... | probing mass orderings in presence of a very light sterile neutrino in a liquid argon detector |
we propose a viable and predictive model based on the $su(3)_c \times su(3)_l \times u(1)_x$ gauge symmetry, supplemented by the global $u(1)_{lg}$ symmetry, the $s_4$ family symmetry and several auxiliary cyclic symmetries, which successfully reproduces the observed sm fermion mass and mixing pattern. the sm charged f... | phenomenological aspects of the fermion and scalar sectors of a $s_4$ flavored 3-3-1 model |
we analyze the dynamics of neutrino gaussian wave-packets, the damping of flavor oscillations and decoherence effects within the framework of extended theories of gravity. we show that, when the underlying description of the gravitational interaction admits a violation of the strong equivalence principle, the parameter... | neutrino decoherence and violation of the strong equivalence principle |
we demonstrate that the finite-time-path field theory is an adequate tool for calculating neutrino oscillations. we apply this theory using a mass-mixing lagrangian which involves the correct dirac spin and chirality structure and a pontecorvo–maki–nakagawa–sakata (pmns)-like mixing matrix. the model is exactly solvabl... | neutrino oscillations in finite time path out-of-equilibrium thermal field theory |
in this work we study the impact of new physics, stimulated by flavor anomalies, on neutrino oscillations through dense dark matter halo. inspired by a model where a majorana dark matter fermion and two new scalar fields contribute to b → sμ+μ- transition at the one loop level, we study the impact of neutrino-dark matt... | imprints of flavor anomalies on neutrino oscillations through dark matter halo |
neutrino flavor conversion is assumed to be induced by right-handed neutrino flavor conversion via seesaw mechanism. neutrino oscillation is the macroscopic phenomenon before all neutrino flavor-flip interactions reaching equilibrium. the model for the hypothesis is the extension by introducing large mass majorana righ... | neutrino oscillation caused by local symmetry broken |
the earth's matter effect is going to play a crucial role in measuring the unknown three-flavor neutrino oscillation parameters at high confidence level in future high-precision long-baseline experiments. we observe that owing to the new degeneracies among the most uncertain oscillation parameters ($\delta_{cp}, \theta... | exploring earth's matter effect in high-precision long-baseline experiments |
the taishan antineutrino observatory (tao or juno-tao) is a satellite detector for the jiangmen underground neutrino observatory (juno). juno aims at simultaneously probing the two main frequencies of three-flavor neutrino oscillations, as well as their interference related to the mass ordering, at a distance of some 5... | tao -- the taishan antineutrino observatory |
the violation of the classical bounds imposed by leggett-garg inequalities has tested the quantumness of neutrino oscillations (nos) over a long distance during the propagation. the measure of quantumness in experimentally observed nos is studied via quantum resource theory (qrt). here, we focus on the trade-off relati... | trade-off relations of quantum resource theory in neutrino oscillations |
neutrino oscillation phenomenology is briefly reviewed, and the impact of the late professor masatoshi koshiba on research on the neutrino oscillation is discussed from the viewpoint of phenomenology. | neutrino oscillation phenomenology and the impact of professor masatoshi koshiba |
the neutrino propagation and oscillations in various gravitational fields are studied. first, we consider the neutrino scattering off a black hole accounting for the neutrino spin precession. then, we study the evolution of flavor neutrinos in stochastic gravitational waves. the astrophysical applications of the result... | neutrino oscillations in gravitational fields and astrophysical applications |
the instability and growth rates of magnetosonic (fast and slow) waves in a dense magnetized plasma due to its coupling with neutrino beam and two-flavor (muon and electron neutrinos) oscillations are studied. the external magnetic field lies in a plane which makes an angle with the direction of wave propagation. the q... | instability and growth rate of magnetosonic waves in quantum plasmas with oblique magnetic field due to coupling of neutrino beam and flavor oscillations |
the increasingly precise neutrino experiments raise the hope for searching for new physics through studying the impact of neutral current (nc) non-standard interactions (nsi) of neutrinos with matter fields. neutrino oscillation experiments along with the elastic coherent $\nu$ nucleus scattering (ce$\nu$ns) experiment... | searching for axial neutral current non-standard interactions of neutrinos by dune-like experiments |
fuv photochemistry and spectroscopy of interstellar icy molecules and materials attract interest because information from these studies yields detailed knowledge about chemical transformations in extraterrestrial environments. to study the photochemistry and spectroscopy of solid interstellar molecules and materials, w... | investigations of photochemistry and spectroscopy of interstellar icy molecules and materials upon excitation with fuv light |
asymptotic giant branch (agb) stars are major contributors of cosmic dust to the interstellar medium. understanding the formation of cosmic dust ejected from these stars is essential to understanding the broader topics of evolution and composition of stellar and interstellar objects in our universe. in this talk, i wil... | circumstellar dust around oxygen-rich mira variables with maser emission |
asymptotic giant branch (agb) stars are major contributors of cosmic dust to the interstellar medium. the dust composition of a circumstellar shell is primarily determined by a star's carbon to oxygen ratio (c/o). carbon-rich stars are expected to have circumstellar shells dominated by amorphous carbon or graphitic car... | modeling dust composition around the carbon-rich star w orionis |
complex organic molecules in the interstellar medium (ism) generally form on the surface of dust particles, so accurate calculation of surface processes is highly important. cosmic dust particles in the ism differ by size and other parameters. here the influence of the presence of small grains on chemical evolution of ... | chemistry of deuterated species in the presence of multiple dust populations |
asymptotic giant branch (agb) stars are major contributors of cosmic dust to the interstellar medium. understanding the formation of cosmic dust ejected from these stars is essential to understanding the broader topics of evolution and composition of stellar and interstellar objects in our universe. we investigate the ... | circumstellar dust around mira variables and the importance of maser emission: preliminary results |
asymptotic giant branch (agb) stars are major contributors of cosmic dust to the interstellar medium. understanding the formation of cosmic dust ejected from these stars is essential to understanding the broader topics of evolution and composition of stellar and interstellar objects in our universe. we investigate the ... | circumstellar dust around mira variables and the importance of maser emission |
context. standing transverse oscillations of coronal loops are observed to operate in two regimes: rapidly decaying, large amplitude oscillations and undamped small amplitude oscillations. in the latter regime the damping should be compensated by energy supply, which allows the loop to perform almost monochromatic osci... | undamped transverse oscillations of coronal loops as a self-oscillatory process |
context. retrograde-propagating waves of vertical vorticity with longitudinal wavenumbers between 3 and 15 have been observed on the sun with a dispersion relation close to that of classical sectoral rossby waves. the observed vorticity eigenfunctions are symmetric in latitude, peak at the equator, switch sign near 20°... | effect of latitudinal differential rotation on solar rossby waves: critical layers, eigenfunctions, and momentum fluxes in the equatorial β plane |
a number of observational and theoretical aspects of solar magnetoconvection are considered in this review. we discuss recent developments in our understanding of the small-scale structure of the magnetic field on the solar surface and its interaction with convective flows, which is at the centre of current research. t... | solar magnetoconvection and small-scale dynamo. recent developments in observation and simulation |
small-scale internetwork (in) magnetic fields are considered to be the main building blocks of quiet sun magnetism. for this reason, it is crucial to understand how they appear on the solar surface. here, we employ a high-resolution, high-sensitivity, long-duration hinode/nfi magnetogram sequence to analyze the appeara... | the solar internetwork. iii. unipolar versus bipolar flux appearance |
context. the tilt of solar active regions described by joy's law is essential for converting a toroidal field to a poloidal field in babcock-leighton dynamo models. in thin flux tube models the coriolis force causes what we observe as joy's law, acting on east-west flows as they rise towards the surface.aims: our goal ... | average motion of emerging solar active region polarities. ii. joy's law |
context. the formation of magnetic flux concentrations within the solar convection zone leading to sunspot formation is unexplained.aims: we study the self-organization of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection.methods: we perform simulations of magnetoconvection i... | magnetic flux concentrations from turbulent stratified convection |
we present measurements of the sun’s sub-surface convective flows and provide evidence that the pattern of supergranulation is driven at the surface. the pattern subsequently descends slowly throughout the near-surface shear layer in a manner that is inconsistent with a 3d cellular structure. the flow measurements are ... | helioseismic imaging of supergranulation throughout the sun’s near-surface shear layer |
we present a comparative analysis of the size of spots in sunspot groups. for the analysis, we have used the characteristics of individual sunspots and pores according to the daily synoptic observations of the kislovodsk mountain astronomical station in solar cycle 24. we have constructed the distribution of area for t... | the characteristic sizes of the sunspots and pores in solar cycle 24 |
aims: our goal is to constrain models of active region formation by tracking the average motion of active region polarity pairs as they emerge onto the surface.methods: we measured the motion of the two main opposite polarities in 153 emerging active regions using line-of-sight magnetic field observations from the sola... | average motion of emerging solar active region polarities. i. two phases of emergence |
numerical modeling of solar and stellar convection, and by extension modeling of solar and stellar dynamos faces a surprising challenge. no hydrodynamic, magnetohydrodynamic, or radiative magnetohydrodynamic model of solar convection, if conducted in a sufficiently deep domain, achieves the velocity power spectrum impl... | deciphering solar convection |
normal-mode coupling is a technique applied to probe the solar interior using surface observations of oscillations. the technique, which is straightforward to implement, makes more use of the seismic information in the wave field than other comparable local imaging techniques and therefore has the potential to signific... | analyzing supergranular power spectra using helioseismic normal-mode coupling |
from solar supergranulation to salt flats in bolivia, from veins on leaves to cells on drosophila wing disks, polygon-based networks exhibit great complexities, yet similarities and consistent patterns emerge. based on analysis of 99 polygonal tessellations with a wide variety of physical origins, this work demonstrate... | e2 and gamma distributions in polygonal networks |
the wealth of observational data available has been instrumental in investigating physical features relevant to solar granulation, supergranulation and active regions. meanwhile, numerical models have attempted to bridge the gap between the physics of the solar interior and such observations. however, there are relevan... | inferring plasma flows at granular and supergranular scales with a new architecture for the deepvel neural network |
convective flows are known as the prime means of transporting magnetic fields on the solar surface. thus, small magnetic structures are good tracers of turbulent flows. we study the migration and dispersal of magnetic bright features (mbfs) in intergranular areas observed at high spatial resolution with sunrise/imax. w... | kinematics of magnetic bright features in the solar photosphere |
aims: we investigate small-scale flux cancelations in a young active region observed with the high-resolution imaging magnetograph imax on the sunrise balloon-borne solar observatory.methods: the observed stokes profiles of the photospheric fe i 5250.2 å line were inverted using the spinor code to obtain the atmospheri... | cancelation of small-scale magnetic features |
we compare horizontal velocities, vertical magnetic fields, and the evolution of trees of fragmenting granules (tfg, also named families of granules) derived in the quiet sun at disk center from observations at solar minimum and maximum of the solar optical telescope (sot on board hinode) and results of a recent 3d num... | dynamics of trees of fragmenting granules in the quiet sun: hinode/sot observations compared to numerical simulation |
we use the synoptic maps of the photospheric magnetic field observed at wilcox solar observatory, mount wilson observatory, kitt peak, soho/mdi, solis/vsm, and sdo/hmi to study the distribution of weak photospheric magnetic field values in 1974-2018. we fit the histogram distribution of weak field values for each synop... | asymmetric distribution of weak photospheric magnetic field values |
supergranules in the quiet sun are outlined by a web-like structure of enhanced magnetic field strength, the so-called magnetic network. we aim to map the magnetic network field around the average supergranule near disk center. we use observations of the line-of-sight component of the magnetic field from the helioseism... | anisotropy of the solar network magnetic field around the average supergranule |
through helioseismic measurement of the sun’s subsurface flows, we assess the rossby number associated with the convective motions. the helioseismic procedure is a new form of the ring-analysis technique that is capable of resolving supergranulation. the extremely fine spatial resolution is achieved by deconvolving the... | helioseismic measurements of the rossby number in the sun's near-surface shear layer |
the statistics of the photospheric supergranulation pattern were investigated using continuum images observed by solar dynamic observatory (sdo)/helioseismic and magnetic imager (hmi) taken at 6713 å. the supergranular boundaries can be extracted by tracking photospheric velocity plasma flows. the ball-tracking method ... | statistics of photospheric supergranular cells observed by sdo/hmi |
a reliable inference of the differential rotation rate of the solar photosphere is essential for models of the solar interior. the work presented here is based on a novel iterative phase correlation technique, which relies on the measurement of the local shift, at the central meridian, between two images separated by a... | measuring solar differential rotation with an iterative phase correlation method |
a new theoretical model for the solar wind is developed that includes the wind's acceleration, conservation of angular momentum, deviations from corotation, and nonradial velocity and magnetic field components from an inner boundary (corresponding to the onset of the solar wind) to beyond 1 au. the model uses a solutio... | a generalized equatorial model for the accelerating solar wind |
some preliminary processing results are presented for a dataset obtained with the solar optical telescope on the hinode satellite. the idea of the project is to record, nearly simultaneously, the full velocity and magnetic-field vectors in growing active regions and sunspot groups at a photospheric level. our ultimate ... | doubts about the crucial role of the rising-tube mechanism in the formation of sunspot groups |
to calculate the magnetic flux and the horizontal movement of coronal bright points (cbps) in relation to supergranular cell boundaries, the time series of the sdo/hmi visible-light continuum images and sdo/aia euv images for 13 february 2011 have been studied. the supergranular lanes were detected in hmi continuum ima... | motion and magnetic flux changes of coronal bright points relative to supergranular cell boundaries |
from solar supergranulation to salt flat in bolivia, from veins on leaves to cells on drosophila wing discs, polygon-based networks exhibit great complexities, yet similarities persist and statistical distributions can be remarkably consistent. based on analysis of 99 polygonal tessellations of a wide variety of physic... | e2 distribution and statistical regularity in polygonal planar tessellations |
in recent studies the dynamic properties of small-scale magnetic fields (magnetic elements [mes]) in the quiet sun were used to investigate peculiar features of turbulent convection and get insights on the characteristic spatial and temporal scales of evolution of magnetic fields, from granular to supergranular. the ai... | the complex nature of magnetic element transport in the quiet sun: the multiscaling character |
context. detailed knowledge of surface dynamics is one of the key points in understanding magnetic solar activity. the motions of the solar surface, to which we have direct access via the observations, tell us about the interaction between the emerging magnetic field and the turbulent fields.aims: the flows computed wi... | texture of average solar photospheric flows and the donut-like pattern |
the spatial-temporal picture of appearance of active regions and the relationship of their appearance with the structure and development of a large-scale magnetic field were studied during the transition from solar cycle 24 to 25. during this period, solar activity is low, and therefore the dynamics of a large-scale ma... | appearance of active regions at the end of solar cycle 24 and at the beginning of cycle 25', 'appearance of active regions at the end of solar cycle 24 and at the beginning of cycle 25', 'appearance of active regions at the end of solar cycle 24 and at the beginning of cycle 25 |
context. fully fledged sunspots are known to be surrounded by a radial outflow called the moat flow.aims: we investigate the evolution of the horizontal flow field around sunspots during their decay, that is, from fully fledged to naked spots, after they loose the penumbra, to the remnant region after the spot has full... | evolution of the flow field in decaying active regions. transition from a moat flow to a supergranular flow |
context. the spatial power spectrum of supergranulation does not fully characterize the underlying physics of turbulent convection. for example, it does not describe the non-gaussianity in the horizontal flow divergence.aims: our aim is to statistically characterize the spatial pattern of solar supergranulation beyond ... | characterizing the spatial pattern of solar supergranulation using the bispectrum |
the spatiotemporal dynamics of vorticity and magnetic field in the region of a photospheric vortex at a supergranular junction of the quiet sun is studied, using hinode's continuum intensity images and longitudinal magnetograms. we show that in a 30-min interval during the vortex lifetime, the magnetic field is intensi... | intensification of magnetic field in merging magnetic flux tubes driven by supergranular vortical flows |
local helioseismology provides a unique opportunity to investigate the subsurface structure and dynamics of active regions and their effect on the large-scale flows and global circulation of the sun. we use measurements of plasma flows in the upper convection zone, provided by the time-distance helioseismology pipeline... | local helioseismology of emerging active regions: a case study |
while the velocity fluctuations of supergranulation dominate the spectrum of solar convection at the solar surface, very little is known about the fluctuations in other physical quantities like temperature or density at supergranulation scale. using observations from the helioseismic and magnetic imager (hmi) onboard t... | intensity contrast of the average supergranule |
aims: although the temporal evolution of active regions (ars) is relatively well understood, the processes involved continue to be the subject of investigation. we study how the magnetic field of a series of ars evolves with time to better characterise how ars emerge and disperse.methods: we examined the temporal varia... | evolution of the magnetic field distribution of active regions |
observational evidence for the origin of active region magnetic fields has been sought from published information on extended solar cycles, statistical distributions of active regions and ephemeral regions, helioseismology results, positional relationships to supergranules, and fine-scale magnetic structure of active r... | observational evidence of shallow origins for the magnetic fields of solar cycles - a review |
aims: despite extensive studies carried out since its discovery half a century ago, the nature of supergranulation remains an open question in solar physics. separability of flow models is a common assumption made in the literature to shed light on the properties of supergranules. this paper studies the ability of sepa... | sdo/hmi observations of the average supergranule are not compatible with separable flow models |
the tilt angle, current helicity and twist of solar magnetic fields can be observed in solar active regions. we carried out estimates of these parameters by two ways. firstly, we consider the model of turbulent convective cells (super-granules) which have a loop floating structure towards the surface of the sun. their ... | estimates of current helicity and tilt of solar active regions and joy's law |
context. in a previous work, we investigated the evolution of the flow field around sunspots during sunspot decay and compared it with the flow field of supergranular cells. the decay of a sunspot proceeds as it interacts with its surroundings. this is manifested by the changes observed in the flow field surrounding th... | evolution of the flow field in decaying active regions. ii. converging flows at the periphery of naked spots |
context. active regions (ars) play an important role in the magnetic dynamics of the sun. solar surface flux transport models (sftms) are used to describe the evolution of the radial magnetic field at the solar surface. the models are kinematic in the sense that the radial component of the magnetic field behaves as pas... | testing solar surface flux transport models in the first days after active region emergence |
the transition region network seen in solar extreme ultraviolet (euv) lines is the extension of the chromospheric network. the network appears as an irregular web-like pattern over the solar surface outside active regions. the average width of transition region network boundaries is obtained from the two-dimensional au... | variation in the width of transition region network boundaries |
we address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere that is called the source surface where the solar wind originates. this calculation must overcome a widely used fundamental assumption about the source surface - the field is normally required to be ... | generation of a north/south magnetic field component from variations in the photospheric magnetic field |
context. trees of fragmenting granules (tfg) and associated flows are suspected to play a major role in the formation of the network in the quiet sun. we investigate the counterparts, in terms of dynamics, of surface structures detectable by high resolution observations in deeper layers up to 15 mm, which are only avai... | link between trees of fragmenting granules and deep downflows in mhd simulation |
recent dedicated hinode polar region campaigns revealed the presence of concentrated kilogauss patches of the magnetic field in the polar regions of the sun, which are also shown to be correlated with facular bright points at the photospheric level. in this work, we demonstrate that this spatial intermittency of the ma... | association of calcium network bright points with underneath photospheric magnetic patches |
we analyze space-based time-series photometry of sun-like stars, mostly in the pleiades, but also field stars and the sun itself. we focus on timescales between roughly 1 hr and 1 day. in the corresponding frequency band these stars display brightness fluctuations with a decreasing power-law continuous spectrum. k2 and... | brightness fluctuation spectra of sun-like stars. i. the mid-frequency continuum |
in this article, we review recent progresses in subsurface flows obtained from two local helioseismology methods: time-distance helioseismology and ring-diagram analysis. we review results in the following four topics: flows beneath sunspots and active regions, supergranular subsurface flows, shallow meridional flow an... | solar subsurface flows from local helioseismology |
context. the evolution of solar active regions is still not fully understood. the growth and decay of active regions have mostly been studied in case-by-case studies.aims: instead of studying the evolution of active regions case by case, we performed a large-scale statistical study to find indications for the statistic... | evolution and motions of magnetic fragments during the active region formation and decay: a statistical study |
the chromospheric network extended to the transition region as the solar euv network disperses at the coronal level. the euv emission lines from the transition region give information about different atmospheric heights. the network properties have been obtained from the daily spectroscopic data from the coronal diagno... | temporal variations of the solar euv network properties |
the properties of solar bipoles based on data from magnetic field observations at mount wilson observatory during the period of 1917-2016 are considered. special attention is given to variations in the size of the bipole magnetic axis during the solar cycle. it is shown that the distribution of the length of the bipole... | influence of supergranulation on the properties of sunspot bipoles |
the study of solar rotation has a 150-year history. early studies were restricted to looking at the movement of sunspots; much later came studies using other tracers such as supergranules, and spectroscopic measurements using doppler shifts of spectral lines. these studies also found evidence of other large-scale flows... | large-scale flows in the sun: characteristics and time variations |
three independent sets of data: (i) series of filtergrams obtained in line caii k (393.416 nm) with the ground-based telescope precision solar photometric telescope (pspt) of mauna loa solar observatory; (ii) series of filtergrams of atmospheric imaging assembly (aia) of the solar dynamics observatory (sdo) in λ160 nm ... | identification of large-scale cellular structures on the sun based on the sdo and pspt data |
it is widely accepted that the interplanetary magnetic field can be, on average, well approximated by the parker field and that the presence of turbulent fluctuations in the solar wind requires a statistical description of the field. a realistic representation of the interplanetary magnetic field lines may be provided ... | stochastic parker spirals in the solar wind: role of the radial field fluctuations and switchbacks |
the methods for reducing the observations from the 150-foot tower telescope on mt. wilson are reviewed, and a new method for determining the poleward and rotational velocity deviations is described and applied. the flows we study are smaller than global and change with the solar cycle, so we describe them as poleward a... | photospheric velocities measured at mt. wilson show rotational and poleward velocity deviations compose the torsional oscillations |
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