Higher-order electron modes in a two-electron-temperature plasma

1990 ◽  
Vol 43 (2) ◽  
pp. 239-255 ◽  
Author(s):  
R. L. Mace ◽  
M. A. Hellberg
Keyword(s):  
Electron Temperature ◽  
Higher Order ◽  
Hot Electron ◽  
Temperature Plasma ◽  
Critical Curves ◽  
Higher Order Modes ◽  
Electron Acoustic Wave ◽  
Electron Acoustic ◽  
Relationship Of ◽  
The Relationship

We discuss critical curves that allow us to predict, qualitatively, the topological behaviour of higher-order modes in a two-electron-temperature plasma as wavenumber and hot electron fraction are varied. The relationship of these higher-order modes to the electron-acoustic wave is elucidated.

Electron-acoustic waves in the laboratory: an experiment revisited

2000 ◽  
Vol 64 (4) ◽  
pp. 433-443 ◽  
Author(s):  
M. A. HELLBERG ◽  
R. L. MACE ◽  
R. J. ARMSTRONG ◽  
G. KARLSTAD
Keyword(s):  
Distribution Function ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
High Frequency ◽  
Hot Electron ◽  
Electron Component ◽  
Temperature Plasma ◽  
Electrostatic Waves ◽  
Electron Acoustic Wave ◽  
Electron Acoustic

High-frequency electrostatic waves have been observed in a two-electron-temperature plasma. Both bi-Maxwellian and Maxwellian-waterbag models were found to be inadequate in explaining the observed dispersion and damping rates. However, modelling of the hot electron component with a κ-distribution function confirms that the experiments represent observation of the electron-acoustic wave in the laboratory.

scholarly journals Generalised Hölderian functions

1989 ◽  
Vol 40 (1) ◽  
pp. 147-155
Author(s):  
S. De Sarkar ◽  
S. Panda
Keyword(s):  
Continuous Functions ◽  
Higher Order ◽  
Positive Order ◽  
New Class ◽  
Lipschitzian Functions ◽  
Relationship Of ◽  
The Relationship ◽  
Class Of Functions

The concept of kth Hölderian functions on an interval [a, b] which generalises the notion of Hölderian (Lipschitzian) functions of positive order on [a, b] is introduced. The relationship of such functions to functions of bounded kth variation and absolutely kth continuous functions is examined. Properties induced by higher order derivatives in this new class of functions are investigated.

Westward travelling surge driven by the polar cap flow channels

2021 ◽  
Author(s):  
Yuzhang Ma ◽  
Qing-He Zhang ◽  
Larry R. Lyons ◽  
Jiang Liu ◽  
Zan-Yang Xing ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Flow Channel ◽  
Polar Cap ◽  
Temperature Plasma ◽  
F Region ◽  
Flow Channels ◽  
Bulge Region ◽  
Low Entropy ◽  
The Relationship ◽  
Region Plasma

<p>Following substorm auroral onset, the active aurora region usually expands poleward toward the poleward auroral boundary. Such poleward expansion is often associated with a bulge region that expands westward and forms the westward travelling surge (WTS). In this paper we show all-sky imager and Poker Flat Advanced Modular Incoherent Scatter Radar (PFISR) radar observations of two surge events to investigate the relationship between the surge and flow from the polar cap. For both events, we observe auroral streamers, with an adjacent flow channel consisting of decreased density and cool electron temperature plasma flowing equatorward. This flow channel appears to impinge and lead/feed surge formation, and to stay connected to the surge as it moves westward. Also, for both events, streamer observations indicate that, following initial surge development, similar flows led to explosive surge enhancements. The observation that the streamers connected to the auroral polar boundary and that the flow channels consisted of low density, low electron temperature plasma indicates that the impinging plasma came from the polar cap. For both events, the altitude variations of F region plasma within the surges are related with aurora emission and the poleward/equatorward flow, and the surges develop strong auroral streamers that initiate along the poleward auroral boundary when contacted with flow from the polar cap. These results suggest that the polar cap flow channels play a crucial role in auroral surges by feeding low entropy plasma into surge initiation and development, and also playing an important role in the dynamics within a surge.</p>

Critical densities for Korteweg–de Vries-like acoustic solitons in multi-ion plasmas

2015 ◽  
Vol 81 (6) ◽  
Author(s):  
Frank Verheest
Keyword(s):  
Acoustic Mode ◽  
Hot Electron ◽  
Temperature Plasma ◽  
De Vries ◽  
Generic Proof ◽  
Parameter Ranges ◽  
Electron Acoustic ◽  
Case Basis ◽  
Velocity Mode ◽  
Quadratic And Cubic Nonlinearities

A generic proof has been given that, for the acoustic mode with the highest velocity in a plasma comprising a number of fluid species and one kind of inertialess electrons, even though there can be critical densities (making the coefficient of the quadratic nonlinearity in a Korteweg–de Vries equation vanish), no supercritical densities exist (requiring the simultaneous annulment of both the quadratic and cubic nonlinearities in a reductive perturbation treatment). Similar conclusions hold upon expansion of the corresponding Sagdeev pseudopotential treatment. When there is only one (hot) electron species, the highest-velocity mode is an ion-acoustic one, but if there is an additional cool electron species, with its inertia taken into account, the highest-velocity mode is an electron-acoustic mode in a two-temperature plasma. The cool fluid species can have various polytropic pressure–density relations, including adiabatic and/or isothermal variations, whereas the hot inertialess electrons are modelled by extensions of the usual Boltzmann description that include non-thermal effects through Cairns, kappa or Tsallis distributions. Together, in this way quite a number of plasma models are covered. Unfortunately, there seems to be no equivalent generic statement for the slow modes, so that these have to be studied on a case-by-case basis, which for models with more than three species is far from straightforward, given the parameter ranges to be discussed.

Parametric decay instability of an upper-hybrid wave in a two-temperature plasma

1994 ◽  
Vol 51 (2) ◽  
pp. 193-200 ◽  
Author(s):  
S. Konar ◽  
V. Rai
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
Density Ratio ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Hot Electron ◽  
Hybrid Wave ◽  
Temperature Plasma ◽  
Band Frequency ◽  
Parametric Decay

Parametric decay of an upper-hybrid pump into another upper-hybrid wave and a low-frequency lower-hybrid mode is considered in a two-electron temperature plasma. Expressions for the nonlinear dispersion relation and growth rate are obtained. It is found that the growth rate is quite sensitive to the hot-electron temperature and the density ratio of the hot and the cold components only when the side-band frequency is close to the second or third harmonic of the cyclotron frequency. The relevance of our investigation to Q machines and the ELMO bumpy torus is pointed out.

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