scholarly journals Hybrid model of inhomogeneous solar wind plasma heating by Alfvén wave spectrum: Parametric studies

2010 ◽  
Vol 115 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
L. Ofman
Keyword(s):  
Solar Wind ◽  
Hybrid Model ◽  
Plasma Heating ◽  
Wave Spectrum ◽  
Solar Wind Plasma ◽  
Alfven Wave ◽  
Parametric Studies

scholarly journals Hybrid models of solar wind plasma heating

2011 ◽  
Vol 29 (6) ◽  
pp. 1071-1079 ◽  
Author(s):  
L. Ofman ◽  
A.-F. Viñas ◽  
P. S. Moya
Keyword(s):  
Solar Wind ◽  
Heavy Ions ◽  
Plasma Heating ◽  
Wave Spectrum ◽  
Solar Wind Plasma ◽  
Ion Temperature ◽  
Temperature Anisotropy ◽  
Streaming Instability ◽  
Turbulent Spectrum

Abstract. Remote sensing and in-situ observations show that solar wind ions are often hotter than electrons, and the heavy ions flow faster than the protons by up to an Alfvén speed. Turbulent spectrum of Alfvénic fluctuations and shocks were detected in solar wind plasma. Cross-field inhomogeneities in the corona were observed to extend to several tens of solar radii from the Sun. The acceleration and heating of solar wind plasma is studied via 1-D and 2-D hybrid simulations. The models describe the kinetics of protons and heavy ions, and electrons are treated as neutralizing fluid.The expansion of the solar wind is considered in 1-D hybrid model. A spectrum of Alfvénic fluctuations is injected at the computational boundary, produced by differential streaming instability, or initial ion temperature anisotropy, and the parametric dependence of the perpendicular heating of H+-He++ solar wind plasma is studied. It is found that He++ ions are heated efficiently by the Alfvénic wave spectrum below the proton gyroperiod.

Ion-scale break of the plasma fluctuation spectra in different large-scale solar wind streams

2021 ◽  
Author(s):  
Maria Riazantseva ◽  
Liudmila Rakhmanova ◽  
Yuri Yermolaev ◽  
Irina Lodkina ◽  
Georgy Zastenker ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Plasma Heating ◽  
Coronal Holes ◽  
Magnetic Clouds ◽  
Alfven Wave ◽  
Slow Solar Wind ◽  
P Value ◽  
High Temporal Resolution ◽  
Turbulent Cascade

<p>Appearance of measurements of the interplanetary medium parameters with high temporal resolution gave rise to a variety of investigations of turbulent cascade at ion kinetic scales at which processes of plasma heating was believed to operate. Our recent studies based on high frequency plasma measurements at Spektr-R spacecraft have shown that the turbulent cascade was not stable and dynamically changed depending on the plasma conditions in different large-scale solar wind structures. These changes was most significant at the kinetic scales of the turbulent cascade. Slow undisturbed solar wind was characterized by the consistency of the spectra to the predictions of the kinetic Alfven wave turbulence model. On the other hand, the discrepancy between the model predictions and registered spectra were found in stream interaction regions characterized by crucial steepening of spectra at the kinetic scales with slopes having values up to -(4-5). This discrepancy was clearly shown for plasma compression region Sheath in front of the magnetic clouds and CIR in front of high speed streams associated with coronal holes. Present study is focused on the break preceding the kinetic scales. Currently the characteristic plasma parameters associated with the formation of the break is still debated. Number of studies demonstrated that the break was consistent with distinct characteristic frequencies for different values ​​of the plasma proton parameter beta βp. Present study consider the ratio between the break frequency determined for ion flux fluctuation spectra according to Spektr-R data and several characteristic plasma frequencies used traditionally in such cases. The value of this ratio is statistically compared for different large-scale solar wind streams. We analyze both the classical spectrum view with two slopes and one break and the spectrum with flattening between magnetohydrodynamic and kinetic scales.  Our results show that for the Sheath and CIR regions characterized typically by βp ≤1 the break corresponds statistically to the frequency determined by the proton gyroradius. At the same time such correspondence are not observed either for the undisturbed slow solar wind with similar βp value or for disturbed flows associated with interplanetary manifestations of coronal mass ejections, where βp << 1. The results also shows that in slow undisturbed solar wind the break is closer to the frequency determined by the inertial proton length. Thus, apparently the transition between streams of different speeds may result in the change of dissipation regimes and plays role in plasma heating at these areas. This work was supported by the RFBR grant No. 19-02-00177a</p>

scholarly journals Investigation of the outer and inner low-latitude boundary layers

2001 ◽  
Vol 19 (9) ◽  
pp. 1065-1088 ◽  
Author(s):  
T. M. Bauer ◽  
R. A. Treumann ◽  
W. Baumjohann
Keyword(s):  
Boundary Layer ◽  
Solar Wind ◽  
Tangential Stress ◽  
Solar Wind Plasma ◽  
Alfven Wave ◽  
Bulk Velocity ◽  
Closed Field ◽  
Low Latitude ◽  
Field Lines ◽  
Low Latitude Boundary Layer

Abstract. We analyze 22 AMPTE/IRM crossings of the day-side low-latitude boundary layer for which a dense outer part can be distinguished from a dilute inner part. Whereas the plasma in the outer boundary layer (OBL) is dominated by solar wind particles, the partial densities of solar wind and magnetospheric particles are comparable in the inner boundary layer (IBL). For 11 events we find a reasonable agreement between observed plasma flows and those predicted by the tangential stress balance of an open magnetopause. Thus, we conclude that, at least in these cases, the OBL is formed by a local magnetic reconnection. The disagreement with the tangential stress balance in the other 11 cases might be due to reconnection being time-dependent and patchy. The north-south component of the proton bulk velocity in the boundary layer is, on average, directed toward high latitudes for both low and high magnetic shear across the magnetopause. This argues clearly against the possibility that the dayside low-latitude boundary layer is populated with solar wind plasma primarily from the cusps. "Warm", counterstreaming electrons that originate primarily from the magnetosheath and have a field-aligned temperature that is higher than the electron temperature in the magnetosheath by a factor of 1–5, are a characteristic feature of the IBL. Profiles of the proton bulk velocity and the density of hot ring current electrons provide evidence that the IBL is on closed field lines. Part of the IBL may be on newly opened field lines. Using the average spectra of electric and magnetic fluctuations in the boundary layer, we estimate the diffusion caused by lower hybrid drift instability, gyroresonant pitch angle scattering, or kinetic Alfvén wave turbulence. We find that cross-field diffusion cannot transport solar wind plasma into the OBL or IBL at a rate that would account for the thickness ( ~ 1000 km) of these sublayers. On the duskside, the dawn-dusk component of the proton bulk velocity in the IBL and magnetosphere is, on average, directed from the nightside toward local noon. Formation of the IBL may also be due to mechanisms operating in the magnetotail.Key words. Magnetospheric physics (magnetopause, cusp and boundary layer; magnetospheath)

scholarly journals Co-existence of whistler waves with kinetic Alfven wave turbulence for the high-beta solar wind plasma

2012 ◽  
Vol 19 (10) ◽  
pp. 102902 ◽  
Author(s):  
Manish Mithaiwala ◽  
Leonid Rudakov ◽  
Chris Crabtree ◽  
Gurudas Ganguli
Keyword(s):  
Solar Wind ◽  
Solar Wind Plasma ◽  
Alfven Wave ◽  
Wave Turbulence ◽  
Whistler Waves ◽  
Kinetic Alfvén Wave ◽  
Kinetic Alfven Wave ◽  
High Beta

scholarly journals On heating of solar wind protons by the breaking of large amplitude Alfvén waves

2018 ◽  
Author(s):  
Horia Comişel ◽  
Yasuhiro Nariyuki ◽  
Yasuhito Narita ◽  
Uwe Motschmann
Keyword(s):  
Solar Wind ◽  
Pitch Angle ◽  
Plasma Heating ◽  
Alfven Waves ◽  
Distribution Functions ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Parametric Decay ◽  
Angle Scattering ◽  
Velocity Distribution Functions

Abstract. By means of hybrid simulations, we present a study on plasma heating by the field-aligned parametric decay of a monochromatic left-handed polarized Alfven wave. Simultaneous multidimensional comparisons of the wave modes and proton kinetics suggest that parametric decay of Alfven waves and pitch angle scattering of solar wind protons are interrelated. Parametric decay mechanism yields counter-propagating Alfven waves that can shape and broaden via pitch angle scattering mechanism both the sunward and antisunward sides of the proton velocity distribution functions in agreement with in situ measurements of fast stream solar wind plasmas.

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