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Destruction of cyclotron resonances in weakly collisional, inhomogeneous plasmas. Memorandum report

Technical Report ·
OSTI ID:5628170
;

It is shown, both analytically and numerically, that cyclotron resonances can be destroyed in dense (..omega../sub rho/ > ..cap omega.. where ..omega../sub rho/ is the plasma frequency and ..cap omega.. is the cyclotron frequency), weakly collisional, inhomogeneous plasmas when (..nu../..cap omega..) k/sup 2/ (r/sub L/)/sup 2/ is somewhat > 1, where ..nu.. is the collision frequency and r/sub L/ is the mean Larmor radius. The theory is based upon a model Fokker-Planck equation. It is found that the particles make a transition from magnetized to unmagnetized behavior. This is an important result since it indicates that the ion- and electron-cyclotron-drift instabilities transform into their unmagnetized counterparts, the lower-hybrid-drift instability and the ion acoustic instability, respectively. The ion-cyclotron-drift instability (or drift-cyclotron instability) is examined in detail and is found to become the lower-hybrid-drift-instability in the region of maximum growth when (..sqrt..(m/sub e//m/sub i/) ..omega../..cap omega../sub i/ somewhat > ..nu../sub ii//..cap omega../sub i/ somewhat > m/sub e//m/sub i/ for T/sub e/ approximately equal T/sub i/ plasmas. The first inequality is required to overcome electron viscous damping, while the second allows the ions to become unmagnetized. Applications to the equatorial F region of the ionosphere and the Tandem Mirror Experiment (TMX) are discussed.

Research Organization:
Naval Research Lab., Washington, DC (USA)
OSTI ID:
5628170
Report Number(s):
AD-A-067827
Country of Publication:
United States
Language:
English

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Related Subjects

640201 -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANALYTICAL SOLUTION
CHARGE DENSITY
COLLISIONAL PLASMA
COLLISIONS
CYCLOTRON RESONANCE
DAMPING
DIFFERENTIAL EQUATIONS
DRIFT INSTABILITY
EARTH ATMOSPHERE
EQUATIONS
EQUATOR
F REGION
FOKKER-PLANCK EQUATION
FUNCTIONS
INHOMOGENEOUS PLASMA
INSTABILITY
ION WAVE INSTABILITY
IONOSPHERE
MAGNETIC FIELDS
MAGNETIC MIRRORS
MATHEMATICS
NUMERICAL ANALYSIS
NUMERICAL SOLUTION
OPEN PLASMA DEVICES
PLANETARY IONOSPHERES
PLASMA
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
RESONANCE
STABILITY
THERMONUCLEAR DEVICES
TMX DEVICES
TRANSFER FUNCTIONS