Theory of the current-driven ion-cyclotron instability in the bottomside ionosphere. Memorandum report

Technical Report · Mon Nov 11 04:00:00 EST 1985

OSTI ID:6102533

Satyanarayana, P; Chaturvedi, P K; Keskinen, M J; Huba, J D; Ossakow, S L

A theory of the current-driven electrostatic ion-cyclotron(EIC) instability in the collisional bottomside ionosphere is presented. It is found that the electron collisions are destabilizing and are crucial for the excitation of the EIC instability in the collisional bottomside ionosphere. Furthermore, the growth rates of the ion cyclotron instability in the bottomside ionosphere maximize for (K-perpendicular) (rho/sub i/) > or = 1 where 2 pi/K-perpendicular is the mode scale size perpendicular to the magnetic field and rho/sub i/ the ion gyroradius. Realistic plasma density and temperature profiles typical of the high-latitude ionosphere are used to compute the altitude dependence of the linear growth rate of the maximally growing modes and critical drift velocity of the EIC instability. The maximally growing modes correspond to observed meter size irregularities and the threshold drift velocity required for the excitation of EIC instability is lower for heavier (NO/sup +/O/sup +/) ions than that for the lighter (H/sup +/) ions. Dupree's resonance broadening theory is used to estimate nonlinear saturated amplitudes for the ion-cyclotron instability in the high-latitude ionosphere. Comparison with experimental observations is also made. It is conjectured that the EIC instability in the bottomside ionosphere could be a source of transversely accelerated heavier ions and energetic heavy-ion conic distributions at higher altitudes.

• Research Organization: Naval Research Lab., Washington, DC (USA)
• OSTI ID: 6102533
• Report Number(s): AD-A-161862/8/XAB; NRL-MR-5656
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALTITUDE
CHARGED PARTICLES
CYCLOTRON INSTABILITY
EARTH ATMOSPHERE
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
GEOGRAPHICAL VARIATIONS
INSTABILITY
IONOSPHERE
IONS
LATITUDE EFFECT
LEPTONS
MAGNETIC FIELDS
PLANETARY IONOSPHERES
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
SATURATION
VARIATIONS