scholarly journals Turbulent heating in an inhomogeneous magnetized plasma slab

2018 ◽  
Vol 84 (3) ◽  
Author(s):  
Michael Barnes ◽  
P. Abiuso ◽  
W. Dorland
Keyword(s):  
Mean Free Path ◽  
Turbulent Energy ◽  
Magnetized Plasma ◽  
Mass Ratio ◽  
Wave Instability ◽  
Astrophysical Plasmas ◽  
Plasma Slab ◽  
Turbulent Heating ◽  
Ion Species ◽  
Turbulent Cascade

Observational evidence in space and astrophysical plasmas with a long collisional mean free path suggests that more massive charged particles may be preferentially heated. One possible mechanism for this is the turbulent cascade of energy from injection to dissipation scales, where the energy is converted to heat. Here we consider a simple system consisting of a magnetized plasma slab of electrons and a single ion species with a cross-field density gradient. We show that such a system is subject to an electron drift wave instability, known as the universal instability, which is stabilized only when the electron and ion thermal speeds are equal. For unequal thermal speeds, we find from quasilinear analysis and nonlinear simulations that the instability gives rise to turbulent energy exchange between ions and electrons that acts to equalize the thermal speeds. Consequently, this turbulent heating tends to equalize the component temperatures of pair plasmas and to heat ions to much higher temperatures than electrons for conventional mass-ratio plasmas.

HelioSwarm: The Nature of Turbulence in Space Plasmas

2021 ◽  
Author(s):  
Harlan Spence ◽  
Kristopher Klein ◽  
HelioSwarm Science Team
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Solar Wind Plasma ◽  
Turbulent Energy ◽  
Space Plasmas ◽  
Plasma Parameters ◽  
Astrophysical Plasmas ◽  
Ion Distributions ◽  
Background Magnetic Field

<p>Recently selected for phase A study for NASA’s Heliophysics MidEx Announcement of Opportunity, the HelioSwarm Observatory proposes to transform our understanding of the physics of turbulence in space and astrophysical plasmas by deploying nine spacecraft to measure the local plasma and magnetic field conditions at many points, with separations between the spacecraft spanning MHD and ion scales.  HelioSwarm resolves the transfer and dissipation of turbulent energy in weakly-collisional magnetized plasmas with a novel configuration of spacecraft in the solar wind. These simultaneous multi-point, multi-scale measurements of space plasmas allow us to reach closure on two science goals comprised of six science objectives: (1) reveal how turbulent energy is transferred in the most probable, undisturbed solar wind plasma and distributed as a function of scale and time; (2) reveal how this turbulent cascade of energy varies with the background magnetic field and plasma parameters in more extreme solar wind environments; (3) quantify the transfer of turbulent energy between fields, flows, and ion heat; (4) identify thermodynamic impacts of intermittent structures on ion distributions; (5) determine how solar wind turbulence affects and is affected by large-scale solar wind structures; and (6) determine how strongly driven turbulence differs from that in the undisturbed solar wind. </p>

scholarly journals Structure function measurements of the intermittent MHD turbulent cascade

1997 ◽  
Vol 4 (3) ◽  
pp. 185-199 ◽  
Author(s):  
T. S. Horbury ◽  
A. Balogh
Keyword(s):  
Energy Transfer ◽  
High Speed ◽  
Solar Wind Plasma ◽  
Turbulent Energy ◽  
Structure Functions ◽  
Order Structure ◽  
Data Sets ◽  
Magnetic Field Data ◽  
Spacecraft Data ◽  
Turbulent Cascade

Abstract. The intertmittent nature of turbulence within solar wind plasma has been demonstrated by several studies of spacecraft data. Using magnetic field data taken in high speed flows at high heliographic latitudes by the Ulysses probe, the character of fluctuations within the inertia] range is discussed. Structure functions are used extensively. A simple consideration of errors associated with calculations of high moment structure functions is shown to be useful as a practical estimate of the reliability of such calculations. For data sets of around 300 000 points, structure functions of moments above 5 are rarely reliable on the basis of this test, highlighting the importance of considering uncertainties in such calculations. When unreliable results are excluded, it is shown that inertial range polar fluctuations are well described by a multifractal model of turbulent energy transfer. Detailed consideration of the scaling of high order structure functions suggests energy transfer consistent with a "Kolmogorov" cascade.

Surface waves in a two-ion-species magnetized plasma

1986 ◽  
Vol 28 (8) ◽  
pp. 1043-1054 ◽  
Author(s):  
N F Cramer ◽  
C -M Yung
Keyword(s):  
Surface Waves ◽  
Magnetized Plasma ◽  
Ion Species

scholarly journals The turbulent environment of low-mass dense cores

2006 ◽  
Vol 2 (S237) ◽  
pp. 24-30 ◽  
Author(s):  
E. Falgarone ◽  
P. Hily-Blant ◽  
J. Pety ◽  
G. Pineau des Forêts
Keyword(s):  
Turbulent Energy ◽  
Injection Rate ◽  
Solar Neighborhood ◽  
Low Velocity ◽  
Gas Condensation ◽  
Dense Cores ◽  
Gas Cooling ◽  
Low Mass ◽  
Impulsive Heating ◽  
Turbulent Cascade

AbstractThe signatures of intermittent dissipation of turbulent energy have been sought in the translucent environment of a low-mass dense core. Molecular line observations reveal a network of narrow filamentary structures, found on statistical grounds to be the locus of the largest velocity shears. Three independent properties of these structures make them the plausible sites of intermittent dissipation of turbulence: (1) gas there is warmer and more diluted than average, (2) it bears the signatures of a non-equilibrium chemistry triggered by impulsive heating due to turbulence dissipation, and (3) the power that these structures radiate in the gas cooling lines (mostly H2) is so large that it balances the total energy injection rate of the turbulent cascade, for a volume filling factor of only a few percents, consistent with other observations in the Solar Neighborhood. These filamentary structures may act as tiny seeds of gas condensation in diffuse molecular gas. They do not exhibit the properties of steady-state low-velocity magneto-hydrodynamic (MHD) shocks, as presently modelled.

Collisional transport for a superthermal ion species in magnetized plasma

1986 ◽  
Vol 36 (3) ◽  
pp. 313-328 ◽  
Author(s):  
F. Cozzani ◽  
W. Horton
Keyword(s):  
Kinetic Equation ◽  
Transport Theory ◽  
A Priori ◽  
Transport Coefficients ◽  
Kinetic Equations ◽  
High Energy ◽  
Magnetized Plasma ◽  
Fractional Density ◽  
Background Ions ◽  
Ion Species

The transport theory of a high-energy ion species injected isotropically in a magnetized plasma is considered for arbitrary ratios of the high-energy ion cyclotron frequency to the collisional slowing down time. The assumptions of (i) low fractional density of the high-energy species and (ii) average ion speed faster than the thermal ions and slower than the electrons are used to decouple the kinetic equation for the high-energy species from the kinetic equations for background ions and electrons. The kinetic equation is solved by a Chapman–Enskog expansion in the strength of the gradients; an equation for the first correction to the lowest-order distribution function is obtained without scaling a priori the collision frequency with respect to the gyrofrequency. Various transport coefficients are explicitly calculated for the two cases of a weakly and a strongly magnetized plasma.

scholarly journals Reflection, Transmission, and Absorption of Vortex Beams Propagation in an Inhomogeneous Magnetized Plasma Slab

2018 ◽  
Vol 66 (8) ◽  
pp. 4194-4201 ◽  
Author(s):  
Haiying Li ◽  
Farideh Honary ◽  
Zhensen Wu ◽  
Qingchao Shang ◽  
Lu Bai
Keyword(s):  
Magnetized Plasma ◽  
Plasma Slab ◽  
Vortex Beams ◽  
Transmission And Absorption

Drift Wave Instability in the Presense of an RF-Field in a Magnetized Plasma

1983 ◽  
Vol 52 (2) ◽  
pp. 492-500 ◽  
Author(s):  
Alexander J. Anastassiades ◽  
Constantine L. Xaplanteris
Keyword(s):  
Magnetized Plasma ◽  
Wave Instability ◽  
Drift Wave

An extended analytical solution of the Boltzmann equation for non-homogeneous fusion and astrophysical plasmas

1988 ◽  
Vol 40 (3) ◽  
pp. 441-453 ◽  
Author(s):  
S. Cuperman ◽  
D. Zoler
Keyword(s):  
Boltzmann Equation ◽  
Analytical Solution ◽  
Free Path ◽  
Density Gradient ◽  
Transport Coefficients ◽  
Spherical Geometry ◽  
Mean Free Path ◽  
Astrophysical Plasmas ◽  
Electron Plasmas ◽  
Gravitational Fields

The perturbative Chapman-Enskog procedure for solving Boltzmann's equation, holding when f1 ≪ f0 (f = f0 + f1 + …), is replaced by a method that is free of such a limitation. This work represents an extension to the case of strongly anisotropic plasma systems and the spherical geometry of that of Campbell (1984, 1986). The solution obtained here is expressed in terms of prescribed ratios of mean free path for collisions, as well as electric and gravitational fields, to the temperature- and density-gradient lengths. This solution is also used to discuss the limitation of the conduction transport coefficients in electron plasmas.

Mutual Iinformation exchange in solar wind density fluctuations

2020 ◽  
Author(s):  
Luca Sorriso-Valvo ◽  
Francesco Carbone ◽  
Daniele Telloni
Keyword(s):  
Solar Wind ◽  
Mutual Information ◽  
Information Flow ◽  
Information Exchange ◽  
Turbulent Energy ◽  
Density Fluctuations ◽  
Slow Solar Wind ◽  
Proton Density ◽  
Mode Decomposition ◽  
Turbulent Cascade

<p>The fluctuations of proton density in the slow solar wind are analyzed by means of joint Empirical Mode Decomposition (EMD) and Mutual Information (MI) analysis. The analysis reveal that, within the turbulent inertial range, the EMD modes associated with nearby scales have their phases correlated, as shown by the large information exchange. This is a qunatitative measure of the information flow occurring in the turbulent cascade. On the other hand, at scales smaller than the ion gyroscale, the information flow is lost, and the mutual information is low, suggesting that in the kinetic range the nonlinear interacions are no longer sustaining a turbulent energy cascade.</p>

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