CGL Invariants and the Moments of the Boltzmann–Vlasov Equation

1974 ◽  
Vol 52 (14) ◽  
pp. 1345-1357 ◽  
Author(s):  
M. Fridman
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Solar Wind ◽  
Vlasov Equation ◽  
Gyration Radius ◽  
Solar Wind Parameters ◽  
Essential Problem ◽  
The Magnetic Field ◽  
Transport Laws ◽  
Good Agreement

The transport laws of the noncollisional systems must be obtained from the Boltzmann–Vlasov equation. The most simple cases are the CGL invariants along the magnetic field. The essential problem is to determine the criteria necessary to close the moments system. The lower order in the gyration radius expansion gives the perpendicular contribution to the heat flux. After expansion with the supersonic conditions, the parallel contribution is obtained, and also the second term of the expansions in which the first term is the "invariant." The numerical value of the heat flux can be considered in good agreement with the solar wind parameters, and the corrections to the invariants are found to agree with previous results (kinetical and 20-moments Grad approximation).

scholarly journals Experimental and numerical investigation of plasma parameters in the magnetosheath

2018 ◽  
Vol 145 ◽  
pp. 03003
Author(s):  
Polya Dobreva ◽  
Monio Kartalev ◽  
Olga Nitcheva ◽  
Natalia Borodkova ◽  
Georgy Zastenker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Numerical Investigation ◽  
Euler Equations ◽  
Ideal Gas ◽  
Bow Shock ◽  
Plasma Parameters ◽  
Wind Spacecraft ◽  
The Magnetic Field ◽  
Good Agreement

We investigate the behaviour of the plasma parameters in the magnetosheath in a case when Interball-1 satellite stayed in the magnetosheath, crossing the tail magnetopause. In our analysis we apply the numerical magnetosheath-magnetosphere model as a theoretical tool. The bow shock and the magnetopause are self-consistently determined in the process of the solution. The flow in the magnetosheath is governed by the Euler equations of compressible ideal gas. The magnetic field in the magnetosphere is calculated by a variant of the Tsyganenko model, modified to account for an asymmetric magnetopause. Also, the magnetopause currents in Tsyganenko model are replaced by numericaly calulated ones. Measurements from WIND spacecraft are used as a solar wind monitor. The results demonstrate a good agreement between the model-calculated and measured values of the parameters under investigation.

Viscomagnetic Heat Flux Experiments as a Test of Gas Kinetic Theory in the Burnett Regime

1978 ◽  
Vol 33 (7) ◽  
pp. 749-760 ◽  
Author(s):  
G. E. J. Eggermont ◽  
P. W. Hermans ◽  
L. J. F. Hermans ◽  
H. F. P. Knaap ◽  
J. J. M. Beenakker
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Heat Flux ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Gas Kinetic Theory ◽  
The Magnetic Field ◽  
Good Agreement

In a rarefied polyatomic gas streaming through a rectangular channel, an external magnetic field produces a heat flux perpendicular to the flow direction. Experiments on this “viscom agnetic heat flux” have been performed for CO, N2, CH4 and HD at room temperature, with different orientations of the magnetic field. Such measurements enable one to separate the boundary layer contribution from the purely bulk contribution by means of the theory recently developed by Vestner. Very good agreement is found between the experimentally determined bulk contribution and the theoretical Burnett value for CO, N2 and CH4 , yet the behavior of HD is found to be anomalous.

The relationship between the magnetic field in the Martian magnetotail and upstream solar wind parameters

1994 ◽  
Vol 99 (A9) ◽  
pp. 17199 ◽  
Author(s):  
H. Rosenbauer ◽  
M. I. Verigin ◽  
G. A. Kotova ◽  
S. Livi ◽  
A. P. Remizov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Wind Parameters ◽  
Upstream Solar Wind ◽  
The Relationship ◽  
The Magnetic Field

Flux stationnaires et supersoniques de protons, paralleles au champ magnétique

1974 ◽  
Vol 52 (23) ◽  
pp. 2402-2421 ◽  
Author(s):  
M. Fridman
Keyword(s):  
Magnetic Field ◽  
Differential Equation ◽  
Heat Flux ◽  
Transport Equations ◽  
Total Loss ◽  
Gyration Radius ◽  
Maximum Order ◽  
Champ Magnétique ◽  
The Magnetic Field

Using the gyration radius as the parameter to expand the differential equation for the moments, the transport equations for highly supersonic flux, which is parallel to the magnetic field, are obtained. The maximum order one can hope to obtain for the invariants is discussed together with the relation between the function of distribution f1 proposed by Whang and that which must result at 1 AU if f1 or a bimaxwellian function are used at the origin. Using f01 at the base (~ 55 Rs) it can be estimated that the total loss of heat flux under 1 AU is of the order of 70% on condition that the values obtained after f1 are utilized.

Short timescale magnetic field fluctuations and their impact on space weather forecasting

2020 ◽  
Author(s):  
Lucia Santarelli ◽  
Paola De Michelis ◽  
Giuseppe Consolini
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Space Weather ◽  
Weather Forecasting ◽  
Activity Level ◽  
Magnetic Signal ◽  
Short Timescale ◽  
Field Fluctuations ◽  
Solar Wind Parameters ◽  
The Magnetic Field

<p>The features of the horizontal intensity of the geomagnetic field fluctuations during a geomagnetically disturbed period are analyzed. The Empirical Mode Decomposition (EMD) method is applied to separate short timescale (T<200 min) and long timescale (T>200 min) magnetic field fluctuations, which have been suggested to be related to different physical processes. The magnetic fluctuations at long timescales (T>200 min) seem to show a large degree of correlation between solar wind parameters and magnetospheric dynamics proxies, while the magnetic field fluctuations at short timescales (T<200 min) seem to be essentially related to internal magnetospheric processes and not directly driven by interplanetary changes.</p><p>Daily maps of the short timescale magnetic field fluctuations during a selected period are analyzed in order to investigate their contribution to the total magnetic signal. The aim is to evaluate the role that the internal magnetospheric processes have on the magnetic signal recorded on the ground and to investigate their dependence on the geomagnetic activity level. A comparison between the two hemispheres is also shown. The obtained results can be useful in the Space weather framework. They show the magnetic field fluctuation forecasting requires the development of models that take into account not only the solar wind parameters but also the internal dynamics of the magnetosphere that although triggered by changes of the interplanetary conditions is not directly driven by solar wind/interplanetary magnetic field.</p>

scholarly journals Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

2005 ◽  
Vol 23 (2) ◽  
pp. 609-624 ◽  
Author(s):  
K. E. J. Huttunen ◽  
J. Slavin ◽  
M. Collier ◽  
H. E. J. Koskinen ◽  
A. Szabo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Speed ◽  
Interplanetary Shock ◽  
Wind Pressure ◽  
Shock Propagation ◽  
Interplanetary Shocks ◽  
Maximum Variance ◽  
The Magnetic Field

Abstract. Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. We found that the maximum variance SI unit vectors were nearly aligned with the associated interplanetary shock normals. For two of the tail lobe SI events during which Cluster was located close to the tail boundary, Cluster observed the inward moving magnetopause. During both events, the spacecraft location changed from the lobe to the magnetospheric boundary layer. During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by collier98 in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well. For events for which we could determine the shock normal orientation, the differences between the observed and calculated shock propagation times from the location of WIND/Geotail to the location of Cluster were small. The propagation speeds of the SIs between the Cluster spacecraft were comparable to the solar wind speed. Our results suggest that the observed tail lobe SIs are due to lateral increases in solar wind dynamic pressure outside the magnetotail boundary.

scholarly journals Solar wind and substorm excitation of the wavy current sheet

2009 ◽  
Vol 27 (6) ◽  
pp. 2457-2474 ◽  
Author(s):  
C. Forsyth ◽  
M. Lester ◽  
R. C. Fear ◽  
E. Lucek ◽  
I. Dandouras ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Current Sheet ◽  
Pressure Pulse ◽  
Wind Pressure ◽  
Expansion Velocity ◽  
Solar Wind Pressure ◽  
Wave Models ◽  
Best Fit ◽  
The Magnetic Field

Abstract. Following a solar wind pressure pulse on 3 August 2001, GOES 8, GOES 10, Cluster and Polar observed dipolarizations of the magnetic field, accompanied by an eastward expansion of the aurora observed by IMAGE, indicating the occurrence of two substorms. Prior to the first substorm, the motion of the plasma sheet with respect to Cluster was in the ZGSM direction. Observations following the substorms show the occurrence of current sheet waves moving predominantly in the −YGSM direction. Following the second substorm, the current sheet waves caused multiple current sheet crossings of the Cluster spacecraft, previously studied by Zhang et al. (2002). We further this study to show that the velocity of the current sheet waves was similar to the expansion velocity of the substorm aurora and the expansion of the dipolarization regions in the magnetotail. Furthermore, we compare these results with the current sheet wave models of Golovchanskaya and Maltsev (2005) and Erkaev et al. (2008). We find that the Erkaev et al. (2008) model gives the best fit to the observations.

scholarly journals Comparison of the measured and modelled electron densities and temperatures in the ionosphere and plasmasphere during 20-30 January, 1993

2000 ◽  
Vol 18 (10) ◽  
pp. 1257-1262 ◽  
Author(s):  
A. V. Pavlov ◽  
T. Abe ◽  
K.-I. Oyama
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Electron Temperature ◽  
Field Line ◽  
Electron Density ◽  
Magnetic Field Line ◽  
New Approach ◽  
Additional Heating ◽  
Vibrational Levels ◽  
The Magnetic Field

Abstract. We present a comparison of the electron density and temperature behaviour in the ionosphere and plasmasphere measured by the Millstone Hill incoherent-scatter radar and the instruments on board of the EXOS-D satellite with numerical model calculations from a time-dependent mathematical model of the Earth's ionosphere and plasmasphere during the geomagnetically quiet and storm period on 20–30 January, 1993. We have evaluated the value of the additional heating rate that should be added to the normal photoelectron heating in the electron energy equation in the daytime plasmasphere region above 5000 km along the magnetic field line to explain the high electron temperature measured by the instruments on board of the EXOS-D satellite within the Millstone Hill magnetic field flux tube in the Northern Hemisphere. The additional heating brings the measured and modelled electron temperatures into agreement in the plasmasphere and into very large disagreement in the ionosphere if the classical electron heat flux along magnetic field line is used in the model. A new approach, based on a new effective electron thermal conductivity coefficient along the magnetic field line, is presented to model the electron temperature in the ionosphere and plasmasphere. This new approach leads to a heat flux which is less than that given by the classical Spitzer-Harm theory. The evaluated additional heating of electrons in the plasmasphere and the decrease of the thermal conductivity in the topside ionosphere and the greater part of the plasmasphere found for the first time here allow the model to accurately reproduce the electron temperatures observed by the instruments on board the EXOS-D satellite in the plasmasphere and the Millstone Hill incoherent-scatter radar in the ionosphere. The effects of the daytime additional plasmaspheric heating of electrons on the electron temperature and density are small at the F-region altitudes if the modified electron heat flux is used. The deviations from the Boltzmann distribution for the first five vibrational levels of N2(v) and O2(v) were calculated. The present study suggests that these deviations are not significant at the first vibrational levels of N2 and O2 and the second level of O2, and the calculated distributions of N2(v) and O2(v) are highly non-Boltzmann at vibrational levels v > 2. The resulting effect of N2(v > 0) and O2(v > 0) on NmF2 is the decrease of the calculated daytime NmF2 up to a factor of 1.5. The modelled electron temperature is very sensitive to the electron density, and this decrease in electron density results in the increase of the calculated daytime electron temperature up to about 580 K at the F2 peak altitude giving closer agreement between the measured and modelled electron temperatures. Both the daytime and night-time densities are not reproduced by the model without N2(v > 0) and O2(v > 0), and inclusion of vibrationally excited N2 and O2 brings the model and data into better agreement.Key words: Ionosphere (ionospheric disturbances; ionosphere-magnetosphere interactions; plasma temperature and density)  

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