scholarly journals Electrostatic analyzer with a 3‐D instantaneous field of view for fast measurements of plasma distribution functions in space

2017 ◽  
Vol 122 (3) ◽  
pp. 3397-3410 ◽  
Author(s):  
X. Morel ◽  
M. Berthomier ◽  
J.‐J. Berthelier
Keyword(s):  
Distribution Functions ◽  
Field Of View ◽  
Electrostatic Analyzer ◽  
Plasma Distribution

scholarly journals Statistical Uncertainties of Space Plasma Properties Described by Kappa Distributions

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 541
Author(s):  
Georgios Nicolaou ◽  
George Livadiotis
Keyword(s):  
Accurate Determination ◽  
Space Plasma ◽  
High Energy ◽  
Distribution Functions ◽  
Kappa Distribution ◽  
Plasma Properties ◽  
Electrostatic Analyzer ◽  
Bulk Parameters ◽  
Plasma Bulk

The velocities of space plasma particles often follow kappa distribution functions, which have characteristic high energy tails. The tails of these distributions are associated with low particle flux and, therefore, it is challenging to precisely resolve them in plasma measurements. On the other hand, the accurate determination of kappa distribution functions within a broad range of energies is crucial for the understanding of physical mechanisms. Standard analyses of the plasma observations determine the plasma bulk parameters from the statistical moments of the underlined distribution. It is important, however, to also quantify the uncertainties of the derived plasma bulk parameters, which determine the confidence level of scientific conclusions. We investigate the determination of the plasma bulk parameters from observations by an ideal electrostatic analyzer. We derive simple formulas to estimate the statistical uncertainties of the calculated bulk parameters. We then use the forward modelling method to simulate plasma observations by a typical top-hat electrostatic analyzer. We analyze the simulated observations in order to derive the plasma bulk parameters and their uncertainties. Our simulations validate our simplified formulas. We further examine the statistical errors of the plasma bulk parameters for several shapes of the plasma velocity distribution function.

An instrument for rapidly measuring plasma distribution functions with high resolution

1982 ◽  
Vol 2 (7) ◽  
pp. 67-70 ◽  
Author(s):  
C.W. Carlson ◽  
D.W. Curtis ◽  
G. Paschmann ◽  
W. Michel
Keyword(s):  
High Resolution ◽  
Distribution Functions ◽  
Plasma Distribution

2π‐radian field‐of‐view toroidal electrostatic analyzer

1988 ◽  
Vol 59 (5) ◽  
pp. 743-751 ◽  
Author(s):  
D. T. Young ◽  
S. J. Bame ◽  
M. F. Thomsen ◽  
R. H. Martin ◽  
J. L. Burch ◽  
...  
Keyword(s):  
Field Of View ◽  
Electrostatic Analyzer

scholarly journals Quasilinear evolution of plasma distribution functions and consequences on wave spectrum and perpendicular ion heating in the turbulent solar wind

2012 ◽  
Vol 19 (4) ◽  
pp. 042704 ◽  
Author(s):  
L. Rudakov ◽  
C. Crabtree ◽  
G. Ganguli ◽  
M. Mithaiwala
Keyword(s):  
Solar Wind ◽  
Wave Spectrum ◽  
Distribution Functions ◽  
Ion Heating ◽  
Plasma Distribution

scholarly journals The κ-cookbook: a novel generalizing approach to unify κ-like distributions for plasma particle modelling

2020 ◽  
Vol 497 (2) ◽  
pp. 1738-1756 ◽  
Author(s):  
K Scherer ◽  
E Husidic ◽  
M Lazar ◽  
H Fichtner
Keyword(s):  
Debye Length ◽  
Distribution Functions ◽  
Energy Distributions ◽  
Pickup Ions ◽  
Plasma Distribution ◽  
Special Cases ◽  
Power Law Exponent ◽  
Velocity Moments ◽  
Analytical Expressions ◽  
Generalized Distribution

ABSTRACT In the literature different so-called κ-distribution functions are discussed to fit and model the velocity (or energy) distributions of solar wind species, pickup ions, or magnetospheric particles. Here, we introduce a generalized (isotropic) κ-distribution as a ‘cookbook’, which admits as special cases, or ‘recipes’, all the other known versions of κ-models. A detailed analysis of the generalized distribution function is performed, providing general analytical expressions for the velocity moments, Debye length, and entropy, and pointing out a series of general requirements that plasma distribution functions should satisfy. From a contrasting analysis of the recipes found in the literature, we show that all of them lead to almost the same macroscopic parameters with a small standard deviation between them. However, one of these recipes called the regularized κ-distribution provides a functional alternative for macroscopic parametrization without any constraint for the power-law exponent κ.

Suprathermal plasma distribution functions with relativistic cut-offs

2019 ◽  
Vol 491 (3) ◽  
pp. 3967-3973
Author(s):  
H-J Fahr ◽  
M Heyl
Keyword(s):  
Distribution Function ◽  
Heat Transport ◽  
Distribution Functions ◽  
The Other ◽  
Pressure Reduction ◽  
Plasma Distribution ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Velocity Moments ◽  
Free Plasma

ABSTRACT In typical plasma physics scenarios, when treated on kinetic levels, distribution functions with suprathermal wings are obtained. This raises the question of how the associated typical velocity moments, which are needed to arrive at magnetohydrodynamic plasma descriptions, may appear. It has become evident that the higher velocity moments in particular, for example the pressure or heat transport, which are constructed as integrations of the distribution function, contain unphysical contributions from particles with velocities greater than the velocity of light. In what follows, we discuss two possibilities to overcome this problem. One is to calculate a maximal, physically permitted, upper velocity, which can be realized in view of the underlying energization processes, and to stop the integration there. The other is to modify the distribution function relativistically so that no particles with superluminal (v ≥ c) velocities appear. On the basis of a typical collision-free plasma scenario, like the plasma in the heliosheath, we obtain the corresponding expressions for electron and proton pressures and can show that in both cases the pressures are reduced compared with their classical values; however, electrons experience a stronger reduction than protons. When calculating pressure ratios, it turns out that these are of the same order of magnitude regardless of which of the two methods is used. The electron, as the low-mass particle, undergoes the more pronounced pressure reduction. It may turn out that electrons and protons constitute about equal pressures in the heliosheath, implying that no pressure deficit need be claimed here.

Computer simulation of a 360° field‐of‐view ‘‘top‐hat’’ electrostatic analyzer

1988 ◽  
Vol 59 (1) ◽  
pp. 146-155 ◽  
Author(s):  
M. J. Sablik ◽  
D. Golimowski ◽  
J. R. Sharber ◽  
J. D. Winningham
Keyword(s):  
Computer Simulation ◽  
Field Of View ◽  
Electrostatic Analyzer

scholarly journals Kinetic entropy-based measures of distribution function non-Maxwellianity: theory and simulations

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
Haoming Liang ◽  
M. Hasan Barbhuiya ◽  
P. A. Cassak ◽  
O. Pezzi ◽  
S. Servidio ◽  
...  
Keyword(s):  
Distribution Function ◽  
Magnetic Reconnection ◽  
Entropy Density ◽  
Distribution Functions ◽  
Local Distribution ◽  
Particle In Cell ◽  
Maxwellian Plasma ◽  
Plasma Distribution ◽  
Maxwellian Distribution Function ◽  
Quantitative Understanding

We investigate kinetic entropy-based measures of the non-Maxwellianity of distribution functions in plasmas, i.e. entropy-based measures of the departure of a local distribution function from an associated Maxwellian distribution function with the same density, bulk flow and temperature as the local distribution. First, we consider a form previously employed by Kaufmann & Paterson (J. Geophys. Res., vol. 114, 2009, A00D04), assessing its properties and deriving equivalent forms. To provide a quantitative understanding of it, we derive analytical expressions for three common non-Maxwellian plasma distribution functions. We show that there are undesirable features of this non-Maxwellianity measure including that it can diverge in various physical limits and elucidate the reason for the divergence. We then introduce a new kinetic entropy-based non-Maxwellianity measure based on the velocity-space kinetic entropy density, which has a meaningful physical interpretation and does not diverge. We use collisionless particle-in-cell simulations of two-dimensional anti-parallel magnetic reconnection to assess the kinetic entropy-based non-Maxwellianity measures. We show that regions of non-zero non-Maxwellianity are linked to kinetic processes occurring during magnetic reconnection. We also show the simulated non-Maxwellianity agrees reasonably well with predictions for distributions resembling those calculated analytically. These results can be important for applications, as non-Maxwellianity can be used to identify regions of kinetic-scale physics or increased dissipation in plasmas.

Plasma distribution functions in the Earth's magnetotail (XGSM∼ −42RE) at the time of a magnetospheric substorm: GEOTAIL/LEP observation

1994 ◽  
Vol 21 (11) ◽  
pp. 1027-1030 ◽  
Author(s):  
S. Machida ◽  
T. Mukai ◽  
Y. Saito ◽  
M. Hirahara ◽  
T. Obara ◽  
...  
Keyword(s):  
Distribution Functions ◽  
Magnetospheric Substorm ◽  
Plasma Distribution

Plasma distribution functions in plasmoids: GEOTAIL observations

2000 ◽  
Vol 26 (3) ◽  
pp. 415-424 ◽  
Author(s):  
T. Mukai
Keyword(s):  
Distribution Functions ◽  
Plasma Distribution
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