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a mechanism for direct acceleration of electrons to extremely high energy ina cold, collisional plasma has been observed. detailed time- and space-resolved measurements (including high-speed movies)on an experiment at caltech reveal the following sequence: a coaxial magnetized plasma gun forms a dense, cold mhd-drivenc... | hard x-rays observed associated with instability of a collisional mhd-driven collimated plasma jet |
it is shown that dissipation of the diamagnetic current heating the coronal plasma with the classical conductivity in the absence of a longitudinal current can increase significantly due to the cellular transverse microstructure of the flux tube, thereby compensating for intense radiative losses. | possible mechanism of enhancement of diamagnetic current dissipation during the heating of magnetic flux tubes in the solar corona |
the solar wind is driven by ion heating in the corona and inner heliosphere, presumably due to dissipation of a turbulent cascade. this heating is observed to be preferentially perpendicular to the large-scale magnetic field, and to act on heavy ions more than on protons. theoretical and observational studies indicate ... | perpendicular ion heating by cyclotron resonant dissipation of turbulently generated kinetic alfvén waves in the solar wind |
the interpretation of remote sensing data in the context of the underlying coronal heating mechanism is complicated by several factors, including limited instrument sensitivity, nonequilibrium ionization and multiple emitting structures along the line of sight. in this poster, we investigate observable signatures of im... | using synthetic and observed timelags to constrain nanoflare heating frequency in active region cores |
the planets and rocky satellites of our solar system show very different evolutions and present-day dynamics. these result from the convective regimes prevailing in their mantle. however, the conditions necessary for convection to generate plate tectonics on earth, episodic resurfacing on venus, heat pipes on io, or no... | thermal convection in a " soft " planetary mantle : plates, plumes, subduction and accretion, and their interactions. |
the physical mechanism that heats the solar corona is one of the still open science questions in solar physics. one of the proposed mechanism for coronal heating are nanoflares. to investigate their role in coronal heating we study the properties of the small-scale heating events in the solar atmosphere using 3d mhd si... | characterisation of small-scale heating events in the solar atmosphere from 3d mhd simulations and their potential role in coronal heating |
thermal instability is a fundamental process of astrophysical plasmas. it is expected to occur whenever the cooling is dominated by radiation and cannot be compensated by heating. this mechanism has been invoked to explain structures at multiple scales in the universe, from the filamentary structure of the ism to the p... | thermal instability-induced fundamental magnetic strands in coronal loops |
the solar corona, the outermost layer of the sun's atmosphere, is heated to temperatures in excess of one million kelvin, nearly three orders of magnitude greater than the surface of the sun. this so-called "coronal heating problem" has occupied the field of solar astrophysics for over seventy years and is one of the m... | diagnosing the frequency of energy deposition in the magnetically-closed solar corona |
motivated by recent rhessi observations that point to the existence of a mechanism that confines electrons to the coronal parts of flare loops more effectively than coulomb collisions, we consider the impact of pitch-angle scattering off turbulent magnetic fluctuations on the parallel transport of electrons in flaring ... | suppression of parallel transport in turbulent magnetized plasmas and its impact on non-thermal and thermal aspects of solar flares |
solar coronal loops are the building blocks of the solar corona. they can be observed in x-ray and extreme ultraviolet (euv), revealing the high plasma temperature (1 mk - 10 mk) of the corona. however, it is still a matter of debate how the magnetic energy is dissipated to heat the coronal plasma. in order to properly... | long-period euv pulsations & coronal rain: multi-scale manifestations of thermal non-equilibrium in the solar atmosphere |
the entire solar system including earth is enveloped in a region of space where the suns magnetic field dominates, this region is called the heliosphere. due to this position in the heliosphere, a strong coupling exists between the sun and our planet. the sun continuously ejects particles, the solar wind, which is comp... | how does o+ outflow vary with solar wind conditions? |
the mechanisms that heat and accelerate the fast and slow wind have not yet been conclusively identified, and their understanding is one of the major science goals of the solar orbiter (so) and solar probe plus (spp) missions. helium abundance and properties in the solar wind are critical tracers for both processes so ... | global multi-fluid solar corona model with alfven wave turbulence |
understanding the energy transfer between different scales is a major challenge in collisionless plasmas. kelvin-helmholtz instability (khi) is a universal shear flow instability taking place in many plasma systems such as magnetospheres of magnetized and non-magnetized planets, solar corona, coronal mass ejectas, astr... | on the cross-scale coupling from fluid-scale kelvin-helmholtz waves into ion and electron scales and associated plasma heating |
the parker solar probe and solar orbiter mark the start of a new era for research on the solar corona and the inner heliosphere. to take full advantage of the datasets that will be produced by these unprecedented missions in order to test the theories proposed to explain coronal heating, the origins of the solar winds ... | a new generation of numerical models and tools for parker solar probe and solar orbiter |
the solar wind is a unique laboratory to study the turbulent processes occurring in a collisionless plasma with high reynolds numbers. a turbulent cascade—the process that transfers the free energy contained within the large scale fluctuations into the smaller ones—is believed to be one of the most important mechanisms... | power spectral density of magnetic field and ion velocity fluctuations from inertial to kinetic range |
solar flares are dramatic events in which magnetic reconnection in the corona leads to heating of plasma to tens of mk and acceleration of particles to high energies. they also centrally involve transport between the corona (where the magnetic reconnection occurs) and the lower solar atmosphere (where most energy is ra... | alfvén waves in solar flares |
state-of-the-art mhd calculations reveal acceptable agreement with observational data for the height profile of the temperature $t(h)$ in the transition region of solar corona. simultaneously, the velocity of the solar wind $u(h)$ has also been calculated. the developed method gives the possibility at given frequency d... | the theory of heating of the solar corona and launching of the solar wind by alfvén waves |
the steady, supersonic outflow from the sun we call the solar wind was first posited in the 1950s and initial theories rightly linked the acceleration of the wind to the existence of the million-degree solar corona. still today, the wind acceleration mechanisms and the coronal heating processes remain unsolved challeng... | magnetic influences on the solar wind (ph.d. dissertation) |
two of the three gases that display isenthalpic joule-thomson (j-t) warming under laboratory conditions are hydrogen and helium, the main constituents of the solar plasma, but the temperatures that are attained by this route are at most a few hundred k. increases in ion temperature by several orders of magnitude are cl... | the contribution of the joule-thomson effect to solar coronal heating |
this article describes the life and work of french astrophysicist evry schatzman (1920-2010). he was a pioneer in the study of white dwarfs during the 1940s and was one of the proponents of the wave heating theory of the solar corona. he made important contributions to the fields of internal stellar structure, novae, m... | evry leon schatzman |
the physics behind the heating of the solar corona and the acceleration of the fast solar wind from coronal holes (predominantly open field regions of the solar corona) is not well understood. recent observations of large-amplitude counter-propagating alfvén waves at the base of coronal holes suggest that the outward a... | study of alfvén wave reflection to address the solar coronal heating problem |
a likely candidate mechanism to heat the solar corona and solar wind is low-frequency "alfvénic" turbulence sourced by magnetic fluctuations near the solar surface. depending on its properties, such turbulence can heat different species via different mechanisms, and the comparison of theoretical predictions to observed... | electron-ion heating partition in imbalanced solar-wind turbulence |
context. the corona of the sun is the part of the solar atmosphere with temperatures of over one million kelvin, which needs to be heated internally in order to exist. this heating mechanism remains a mystery; we see large magnetically active regions in the photosphere lead to strong extreme uv (euv) emission in the co... | coronal bright point statistics. i. lifetime, shape, and coronal co-rotation |
we present new x-ray observations of the optically-obscured protostar hl tau and the intermediate mass herbig be star hd 100546. both objects are surrounded by spectacular disks showing complex morphology including rings and gaps that may have been sculpted by protoplanets. hl tau was detected as a variable hard x-ray ... | x-ray emission and disk irradiation of hl tau and hd 100546 |
the solar atmosphere shows anomalous variation in temperature, starting from the 5500 k photosphere to the million-degree kelvin corona. the corona itself expands into the interstellar medium as the free streaming solar wind, which modulates and impacts the near-earth space weather. the precise source regions of differ... | heating and dynamics of the solar atmosphere |
the magnetic network extending from the photosphere (solar radius ≃ r⊙) to the lower corona ( r_⊙ +10 mm) plays an important role in the heating mechanisms of the solar atmosphere. here we develop further the models of the authors with realistic open magnetic flux tubes, in order to model more complicated configuration... | modelling 3d magnetic networks in a realistic solar atmosphere |
data obtained in the framework of the interball-tail probe (1995-2000) and rhessi (from 2002 to the present) projects have revealed variations in the x-ray intensity of the solar corona in the photon energy range of 2-15 kev during the period of the quiet sun. previously, a hypothesis was proposed that this phenomenon ... | mechanism of heating the solar corona in the splitting of massive photon pairs |
it is well established that transverse mhd waves are ubiquitous in the solar corona. one of the possible mechanisms for heating both open (e.g., coronal holes) and closed (e.g., coronal loops) magnetic field regions of the solar corona is mhd wave-driven turbulence. in this work, we study the variation of the filling f... | how does transverse mhd wave-driven turbulence influence the density filling factor in the solar corona? |
in the context of the solar atmosphere, we re-examine the role of neutral and ionized species in dissipating the ordered energy of intermediate-mode mhd waves into heat. we solve conservation equations for the hydrodynamics and for hydrogen and helium ionization stages, along closed tubes of magnetic field. first, we e... | inevitable consequences of ion-neutral damping of intermediate mhd waves in sun-like stars |
nearly all low-mass stars are believed to exhibit subsurface convection, some level of magnetic dynamo activity, and radiative emission from chromospheric (t = 10,000 k) and coronal (t > 1 million k) layers above their photospheres. linsky et al. (2020) highlighted the usefulness of comparing x-ray and h i lyman alp... | chromospheric and coronal heating in cool stars: constraints on physical processes from x-ray and lyman alpha observations |
most m dwarf flares exhibit a strong response in the x-ray and near-ultraviolet (nuv), which is in line with the neupert effect and the standard heating scenario for less energetic solar flares. however, some flares produce only bright x-rays (quasi-neupert) and others only a bright nuv response (non-neupert). our fund... | high-time resolution physics in stellar flares from a 7-day multi-wavelength campaign on au mic |
interplanetary coronal mass ejections (icmes) and high speed streams (hsss) are noteworthy drivers of disturbance of interplanetary space. interaction between them can cause several phenomena, such as; generation of waves, enhanced geo-effectiveness, particle acceleration, etc. however, how does thermodynamic propertie... | distinct polytropic behavior of plasma during icme-hss interaction |
m dwarf flares observed by the transiting exoplanet survey satellite (tess) sometimes exhibit a peak-bump light-curve morphology, characterized by a secondary, gradual peak well after the main, impulsive peak. a similar late phase is frequently detected in solar flares observed in the extreme ultraviolet from longer ho... | a possible mechanism for the "late phase" in stellar white-light flares |
determination of the three-dimensional (3d) thermodynamic structure of the solar corona by observational means is of great importance to advance the understanding of the physical mechanisms responsible for coronal heating, as well as for the development of global magnetohydrodynamic (mhd) models of the corona. oriented... | reconstrucción tridimensional de la velocidad del viento solar mediante tomografía lyman-α |
the relationship between coronal mass ejections (cmes) and flares is an important issue in solar and stellar physics. the studies on the origination and generation mechanisms of interplanetary cme (icme) materials are crucial for understanding the connection between cmes and flares. the materials inside icmes can be cl... | the contribution and fip bias of three types of materials inside icmes associated with different flare intensities |
the exploration of the inner heliosphere by the parker solar probe has revealed a highly structured solar wind with ubiquitous deflections from the parker spiral, known as switchbacks. interchange reconnection (ir) may play an important role in generating these switchbacks, by forming unstable particle distributions th... | ion kinetics of plasma interchange reconnection in the lower solar corona |
context. it is well known among the scientific community that solar flare activity often begins well before the main impulsive energy release. however, a consistent explanation for this phenomenon has not yet been established.aims: our aim is to investigate the earliest phase of four distinct flares observed by solar o... | the existence of hot x-ray onsets in solar flares |
a large amount of the radiated energy during solar and stellar flares is emitted as white-light continuum emission, extending through the ultraviolet and optical wavelength regimes. broadband photometry and optical spectral observations of m dwarf flares suggest that the white-light peak is located in the near-ultravio... | time-resolved near-ultraviolet flare spectra with the hubble space telescope / cosmic origins spectrograph |
phase mixing of plasma waves leads to the evolution of increasingly smaller-scale perturbations, eventually leading to viscous or resistive dissipation of energy (chen 2021). this has been suggested as a potential cause of solar coronal heating, though the details of the exact mechanisms involved are still unclear. we ... | energy dissipation by kinetic alfven waves in sheared magnetic fields |
one of the possible mechanisms for heating the solar atmosphere is the magnetic reconnection occurring at different spatiotemporal scales. the discovery of fast bursty nanojets due to reconnection in the coronal loops has been linked to nanoflares and is considered as a possible mechanism for coronal heating. the occur... | hi-c 2.1 observations of reconnection nanojets |
we'll review the current state-of-the-art for ground-based instrumentation and techniques to achieve high-resolution observations. we'll use the 4m daniel k. inouye solar telescope (dkist), the european solar telescope (est) and other ground-based instrumentation as examples to demonstrate instrument designs and observ... | ground-based instrumentation and observational techniques |
evidence for the presence of ion cyclotron waves (icws), driven by turbulence, at the boundaries of the current sheet is reported in this paper. by exploiting the full potential of the joint observations performed by parker solar probe and the metis coronagraph on board solar orbiter, local measurements of the solar wi... | does turbulence along the coronal current sheet drive ion cyclotron waves? |
the excess temperature of the solar corona over the photosphere poses a challenge. multiple energetic events contribute to maintaining the corona at such high temperatures. the energy released in different events can vary across several orders of magnitude. large energy events of geomagnetic importance like flares and ... | energetics of the solar atmosphere |
the solar corona is hundreds of times hotter than the visible surface below. the details of the physical mechanisms involved in energizing the solar atmosphere continue to elude scientists. this plasma flows outward from the sun, becoming the solar wind, where it reaches super-alfvénic speeds, filling the solar system ... | outstanding questions of coronal heating and solar wind physics |
context. coronal bright points (bps) are numerous, bright, small-scale dynamical features found in the solar corona. bright points have been observed to exhibit intensity oscillations across a wide range of periodicities and are likely an important signature of plasma heating and/or transport mechanisms.aims: we presen... | automated analysis of oscillations in coronal bright points |
solarc euvst 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 fundamental step for answering how the plasma univ... | science objectives and current status of solar-c_euvst |
the k-distribution function provides a microscopic description of statistical information on the energetic charged particle distributions and is an invaluable aid towards the determination of macroscopic parameters (energetic ion moments) that are fundamentally important for studying the source, loss, transport and acc... | cassini/mimi measurements of energetic ion moments and the polytropic index in saturn's magnetosphere. |
we have measured the root-mean-square (rms) amplitude of intensity fluctuations in plume and interplume regions of a polar coronal hole. these intensity fluctuations correspond to density fluctuations. using data from the sun watcher using active pixel system detector and image processing (swap) on the project for onbo... | density fluctuations in a polar coronal hole; no |
in the standard picture of plasma turbulence, energy injected at large scales cascades conservatively to small scales, eventually thermalizing to heat particles via a variety of mechanisms. this leads to the ''zeroth law of turbulence,'' whereby the macroscopic statistics of the flow and magnetic field are independent ... | violation of the zeroth law of turbulence through the helicity barrier effect |
recent observations by the extreme ultraviolet imager (eui) onboard solar orbiter have revealed prevalent small-scale transient brightenings in the quiet solar corona termed campfires. to understand the generation mechanism of these coronal brightenings, we constructed a self- consistent and time-dependent quiet-sun mo... | transient small-scale brightenings in the quiet sun corona: a model for "campfires" observed with solar orbiter |
the presence of condensations in the solar corona has the potential to be an important diagnostic of coronal heating. we present the results of models of nanoflare heated coronal loops using the 1-d hydrodynamic argos code. the nanoflares are modeled by discrete pulses of energy along the loop. we explore the occurrenc... | modeling of condensations in coronal loops produced by nanoflares with variable frequency and location |
context. the study explores the photospheric magnetic properties of bright and faint small-scale loop systems in the solar atmosphere of the quiet sun, also known as x-ray or coronal bright points.aims: to understand how plasma confined in small-scale loops is heated to million degrees, the loop-associated photospheric... | photospheric magnetic flux and coronal emission properties of small-scale bright and faint loops in the quiet sun |
the solar ultraviolet intensities of spectral lines originating from li- and na-like ions have been observed to surpass the expectations derived from plasmas with coronal approximation. the violation of the coronal approximation can be partially attributed to non-equilibrium ionization (nei) due to dynamic processes oc... | anomalous emission from li- and na-like ions in the corona heated via alfvén wave |
in kagome metals, the chiral current order $\eta$ with time-reversal-symmetry-breaking is the source of various exotic electronic states, while the method of controlling the current order and its interplay with the star-of-david bond order $\phi$ are still unsolved. here, we reveal that tiny uniform orbital magnetizati... | drastic magnetic-field-induced chiral current order and emergent current-bond-field interplay in kagome metal av3sb5 (a=cs,rb,k) |
a new spin-dependent deflection mechanism is revealed by considering the spin-correlated radiation-reaction force during laser-electron collision. we found that such deflection originates from the non-zero work done by the radiation-reaction force along the laser polarization direction in each half-period, which is lar... | spin-dependent radiative deflection in the quantum radiation-reaction regime |
we present the results of the pulse-amplitude-resolved spectroscopy of the accreting pulsar v 0332+53 using the nustar observations of the source in 2015 and 2016. we investigate the dependence of the energy of the cyclotron resonant scattering feature (crsf) as a function of x-ray luminosity on timescales comparable w... | changes in the cyclotron line energy on short and long timescales in v 0332+53 |
this paper describes an analysis of the nustar data of the fastest-rotating magnetar 1e 1547 - 5408, acquired in 2016 april for a time lapse of 151 ks. the source was detected with a 1-60 kev flux of 1.7 × 10-11 erg s-1 cm-2, and its pulsation at a period of 2.086710(5) s. in 8-25 kev, the pulses were phase-modulated w... | a nustar confirmation of the 36 ks hard x-ray pulse-phase modulation in the magnetar 1e 1547.0 - 5408 |
recent observations of frb 20190520b have revealed rapid (tens of s) fluctuation of its dispersion measure within apparently fixed bounds, as well as a reversal of its rotation measure. the fluctuations of dispersion measure are uncorrelated with the intervals between bursts, setting upper bounds $\sim 10\,$ s on any c... | the environment and constraints on the mass of frb 190520b |
transport in hot and dilute, i.e., collisionless, astrophysical and space, plasmas is called "anomalous." this transport is due to the interaction between the particles and the self-generated turbulence by their collective interactions. the anomalous transport has very different and not well known properties compared t... | turbulent transport in 2d collisionless guide field reconnection |
the outer-crust structure and composition of a cold, non-accreting magnetar are studied. we model the outer crust to be made of fully equilibrated matter where ionized nuclei form a coulomb crystal embedded in an electron gas. the main effects of the strong magnetic field are those of quantizing the electron motion in ... | outer crust of a cold non-accreting magnetar |
the first confirmed periodically varying 6.031 and 6.035 ghz hydroxyl masers are reported here. they vary contemporaneously with the 6.7 ghz methanol masers in g323.459-0.079. the 1.665 ghz hydroxyl and 12.2 ghz methanol masers associated with g323.459-0.079 are also periodic. evidence for periodicity is seen in all fe... | synchronized periodic maser flares of multiple oh and ch3oh lines in g323.459-0.079 |
vertically stratified shearing box simulations of magnetorotational turbulence commonly exhibit a so-called butterfly diagram of quasi-periodic azimuthal field reversals. however, in the presence of hydrodynamic convection, field reversals no longer occur. instead, the azimuthal field strength fluctuates quasi-periodic... | convective quenching of field reversals in accretion disc dynamos |
astrophysical flows exhibit rich behaviour resulting from the interplay of different forms of energy--gravitational, thermal, magnetic and radiative. for magnetic cataclysmic variable stars, material from a late, main sequence star is pulled onto a highly magnetized (b>10 mg) white dwarf. the magnetic field is suffi... | laboratory analogue of a supersonic accretion column in a binary star system |
three high-mass x-ray binaries have been discovered recently exhibiting enormous spin-up rates. conventional accretion theory predicts extremely high-surface dipolar magnetic fields that we believe are unphysical. instead, we propose quite the opposite scenario; some of these pulsars exhibit weak magnetic fields, so mu... | not an oxymoron: some x-ray binary pulsars with enormous spin-up rates reveal weak magnetic fields |
neutron stars are a prime laboratory for testing physical processes under conditions of strong gravity, high density, and extreme magnetic fields. among the zoo of neutron star phenomena, magnetars stand out for their bursting behavior, ranging from extremely bright, rare giant flares to numerous, less energetic recurr... | dissecting magnetar variability with bayesian hierarchical models |
context. the magnetic field is a crucial ingredient of neutron stars. it governs the physics of accretion and of the resulting high-energy emission in accreting pulsars. studies of the cyclotron resonant scattering features (crsfs) seen as absorption lines in the x-ray spectra of the pulsars permit direct measurements ... | swift/bat measurements of the cyclotron line energy decay in the accreting neutron star hercules x-1: indication of an evolution of the magnetic field? |
a joint analysis is done of the radio and x-ray observations of sn 1993j. it is argued that neither synchrotron cooling behind the forward shock nor thermal cooling behind the reverse shock is supported by observations. in order for adiabatic models to be consistent, a reinterpretation of the radius of the spatially re... | joining radio with x-rays: a revised model for sn 1993j |
we present a comprehensive timing and spectral analysis of the hmxb 4u 1538-522 by using the nuclear spectroscopic telescope array (nustar) observatory data. using three archived observations made between 2019 and 2021, we have detected ~ 526 s coherent pulsations up to 60 kev. we have found an instantaneous spin-down ... | torque reversal and cyclotron absorption feature in hmxb 4u 1538-522 |
a simple model of chiral asymmetry is proposed to interpret the origin of the strong toroidal magnetic field. the electrons relevant to dynamics forming the the field are in a quantume degenerate state with ultra-relativistic fermi energy. the system is described by dirac hartree fock method using scaled h-bar method. ... | origin of the strong toroidal magnetic field in magnetars |
models invoking magnetic reconnection as the particle acceleration mechanism within relativistic jets often adopt a gradual energy dissipation profile within the jet. however, such a profile has yet to be reproduced in first-principles simulations. here we perform a suite of 3d general relativistic magnetohydrodynamic ... | striped jets in post-neutron star merger systems |
an analytic model of the time-dependent electric and magnetic fields of an astrophysical jet is presented. these fields satisfy the time-dependent faraday’s law and describe a jet with increasing length. the electric field contains both electrostatic and inductive parts. the electrostatic part corresponds to the rate o... | analytic model for the time-dependent electromagnetic field of an astrophysical jet |
we show that the neutrino chirality flip, that can take place in the core of a neutron star at birth, is an efficient process to allow neutrinos to anisotropically escape, thus providing a to induce the neutron star kick velocities. the process is not subject to the {\it no-go theorem} since although the flip from left... | lower bound for the neutrino magnetic moment from kick velocities induced at the birth of neutron stars |
during a one-hour interval of interplanetary magnetic field (imf) bz ≈ 0 nt, the equatorial spacecraft double star tc-1 encountered the dawn flank magnetopause many times at the magnetic local time (mlt) of about 08:00 and the latitude of about -27°. during each encounter, reconnection jets were observed with their vel... | quasi-continuous reconnection accompanied by ftes during imf bz ≈ 0 nt observed by double star tc-1 at the dawnside magnetopause |
accretion shocks in young stellar objects (yso) are a subject of great interest in astrophysics; they exhibit intense magnetic activity and are surrounded by an accretion disk from which matter falls down onto the stellar surface in the form of columns following the magnetic lines (b ~ kg) at the free-fall velocity (10... | laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field: recent results and new exeprimental studies |
star-like amphiphilic polyacrylamide (shpam), consisting of nano-sio2 as the core and a layer of amphiphilic chains as the shell, having two gradient molecular weights, was prepared via a facile method. to elucidate its enhanced oil recovery (eor) potential, the viscoelastic flow and displacement efficiency of shpam we... | viscoelastic displacement and anomalously enhanced oil recovery of a novel star-like amphiphilic polyacrylamide |
exoplanets hat-p-7b and corot-2b have an unusual quirk: instead of having eastward equatorial winds, like the majority of hot jupiters, these two hot jupiters have westward winds. a new study explores whether magnetic fields cause this odd reversal.blowing the wrong wayartists impression of hat-p-7b, an inflated hot ju... | reversing winds on hot jupiters |
magnetic fields are ubiquitous in nature, with currents sheets found on numerous stellar bodies. here, we model plasma diamagnetism's affects in the current sheet in a earth-like magnetotail. a commonly used analytic model for magnetic field reversals is the harris equilibrium. in this model, the particle motion is com... | effects of diamagnetism onmagnetotail current sheet equilibrium |
in this study, we investigated the time-independent dynamics (disc structure, forces and torques) of a quasi-keplerian disc around a millisecond pulsar (msp) with an internal dynamo. we considered the disc around a msp to be divided into the inner, middle and outer regions. by assuming that the disc matter flows in a q... | on the structure of quasi-keplerian accretion discs surrounding millisecond x-ray pulsars |
we present new results of fully general relativistic magnetohydrodynamic (grmhd) simulations of binary neutron star (bns) mergers performed with the whisky code. all the models use a piecewise polytropic approximation of the apr4 equation of state (eos) for cold matter, together with a ''hybrid'' part to incorporate th... | general relativistic magnetohydrodynamic simulations of binary neutron star mergers with the apr4 equation of state |
the influence of positronium photoionization rate on the heating of psr j0250+5854 polar cap is considered. it is assumed that the polar cap is heated only by reverse positrons accelerated in pulsar diode. it is supposed that pulsar diode is located near the star surface (polar cap model) and operates in the steady sta... | the influence of positronium photoionization rate on the heating of j0250+5854 polar cap |
a novel experiment resembling a planar plasma gun has been developed to produce magnetically driven high-energy-density (hed) plasma jets on the 1 ma, 220 ns rise time cobra generator at cornell university. the experimental setup consists of a central pin electrode that injects a single gas puff on axis, surrounded by ... | extended magnetohydrodynamic effects on dynamics and stability of magnetically driven high energy density plasma jets |
we present the results from the australian long baseline array (lba) observations of the ground- and excited-state oh masers at high resolutions towards the massive star-forming region g351.417+0.645 in 2012. we obtain the most accurate spatial gradient of magnetic fields at ground state transitions and verify the reli... | lba high resolution observations of ground- and excited-state oh masers towards g351.417+0.645 |
the influence of the positronium photoionization rate on the polar cap x-ray luminosity of old radio pulsars is considered. it is assumed that the polar cap is heated only by reverse positrons accelerated in the pulsar diode. it is supposed that the pulsar diode is in a stationary state with the lower plate located nea... | the influence of the positronium photoionization rate on the polar cap x-ray luminosity of radio pulsars |
scan quantum mechanics is a novel interpretation of some aspects of quantum mechanics in which the superposition of states is only an approximate effective concept. quantum systems scan all possible states in the superposition and switch randomly and very rapidly among them. a crucial property that we postulate is quan... | quantum inertia stops superposition: scan quantum mechanics |
w49 a is a star-forming region (sfr) found in the constellation of aquila. it contains 3 active regions: w49 north (w49 n), w49 south west (w49 sw) and w49 south (w49 s). we present preliminary results from two epochs (e-)merlin observations of all ground-state oh masers towards the star-forming region (sfr) complex w4... | full polarization analysis of oh masers at 18-cm toward w49 a star forming region |
radio pulsar j0250+5854 is the slowest pulsar among rotation powered pulsars. it is an old pulsar with spin-down age τ = 13.7 · 106 years, which rotates with period p = 23.54 s, the strength of dipolar magnetic field at pole estimated by pulsar spin-down rate is bdip = 5.1 · 1013 g [1]. such pulsars lie beyond conventi... | the influence of small-scale magnetic field on the heating of j0250+5854 polar cap |
masers provide an important, high-resolution probe of the near-circumstellar environment of late-type evolved stars. sio maser polarization may be key in characterizing their magnetic fields. however, the detailed mechanisms responsible for the polarization of sio masers in their near-circumstellar environments continu... | observational and theoretical studies of sio maser polarization toward late-type evolved stars: insights from evpa reversal features |
the afrl shiva star capacitor bank (1300 μf, up to 120 kv) used typically at 4 to 5 mj stored energy, 10 to 15 ma current, 10 μs current rise time, has been used to drive metal shell (solid liner) implosions for compression of axial magnetic fields to multi-megagauss levels, suitable for compressing magnetized plasmas ... | magnetized inertial fusion (mif) research at the shiva star facility |
the use of an induction motor requires the process of stopping the motor speed quickly, using mechanically and electrically generated braking torque. dynamic braking, which is done by making a magnetic field stationary motor. this condition is carried out by injecting a dc current into the three phase induction motor s... | dynamic braking application on three phase induction motor using plc |
the influence of surface small-scale magnetic field on the heating of psr j0250+5854 polar cap is considered. it is assumed that the polar cap is heated only by reverse positrons accelerated in pulsar diode. it is supposed that pulsar diode is located near the star surface (polar cap model) and operates in the steady s... | the influence of small-scale magnetic field on the heating of j0250+5854 polar cap |
we show that the neutrino chirality flip, which can take place in the core of a neutron star at birth, is an efficient process to allow neutrinos to anisotropically escape, thus providing a to induce the neutron star kick velocities. the process is not subject to the no-go theorem since although the flip from left- to ... | lower bound for the neutrino magnetic moment from kick velocities induced at the birth of neutron stars |
recently, some fast radio bursts (frbs) have been reported to exhibit complex and diverse variations in faraday rotation measurements (rm) and polarization, suggesting that dynamically evolving magnetization environments may surround them. in this paper, we investigate the faraday conversion (fc) effect in a binary sys... | polarization evolution of fast radio burst sources in binary systems |
the scattering of neutral particles by an atomic nucleus can lead to electronic ionization and excitation through a process known as the migdal effect. we revisit and improve upon previous calculations of the migdal effect, using the dirac-hartree-fock method to calculate the atomic wave functions. our methods do not r... | precise predictions and new insights for atomic ionization from the migdal effect |
due to the low nuclear recoils, sub-gev dark matter (dm) is usually beyond the sensitivity of the conventional dm direct detection experiments. the boosted and migdal scattering mechanisms have been proposed as two new complementary avenues to search for light dm. in this work, we consider the momentum-transfer effect ... | new strong bounds on sub-gev dark matter from boosted and migdal effects |
we provide a mathematica package, directdm, that takes as input the wilson coefficients of the relativistic effective theory describing the interactions of dark matter with quarks, gluons and photons, and matches it onto an effective theory describing the interactions of dark matter with neutrons and protons. the nonpe... | directdm: a tool for dark matter direct detection |
in most direct detection experiments, the free nuclear recoil description of dark matter scattering breaks down for masses ≲100 mev , or when the recoil energy is comparable to a few times the typical phonon energy for dark matter lighter than 1 mev, scattering via excitation of a single phonon dominates and has been c... | dark matter direct detection from the single phonon to the nuclear recoil regime |
in this letter, we show that the wino-higgsino dark matter (dm) is detectable in near future dm direct detection experiments for almost all consistent parameter space in the spontaneously broken supergravity (sugra) if the muon g - 2 anomaly is explained by the wino-higgsino loop diagrams. we also point out that the pr... | wino-higgsino dark matter in mssm from the g - 2 anomaly |
the low-background, vuv-sensitive 3-inch diameter photomultiplier tube r11410 has been developed by hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. we present the results from the joint effort between the xenon collaboration and the hamamatsu company to produce a highly... | lowering the radioactivity of the photomultiplier tubes for the xenon1t dark matter experiment |
one of the next frontiers in dark-matter direct-detection experiments is to explore the mev to gev mass regime. such light dark matter does not carry enough kinetic energy to produce an observable nuclear recoil, but it can scatter off electrons, leading to a measurable signal. we introduce a semianalytic approach to c... | modulation effects in dark matter-electron scattering experiments |
the most sensitive haloscopes that search for axion dark matter through the two photon electromagnetic anomaly convert axions into photons through the mixing of axions with a large background direct current (dc) magnetic field. in this work we apply the poynting theorem to the resulting axion modified electrodynamics a... | poynting vector controversy in axion modified electrodynamics |
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