Generation of Alfven waves by deceleration of magnetospheric convection and broadband PI pulsations

Journal Article · Sat May 01 04:00:00 EDT 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA087iA05p03511· OSTI ID:5098587

Kan, J R; Lee, L C; Chiu, Y T; Longenecker, D U

It is shown that Alfven waves can be generated in the magnetosphere by the deceleration of magnetospheric convection due to the dynamo process in the magnetosphere-ionosphere coupling. The growth rate of Alfven wave packets bouncing between hemispheres is given by ..gamma..oapprox. =(2/..mu../sub 0/ ..sigma..l) (..cap alpha mu../sub 0//sup 2/..sigma../sub p//sup 2/V/sub 0y//sup 2/-1) where ..cap alpha.. is a dimensionless constant (approx.0.5), ..mu../sub 0/ is the free space permeability, ..sigma../sub p/ is the height-integrated Pedersen conductivity, l is the field line length between hemispheres, V/sub 0y/ is the convection speed in the magnetospheric dynamo region. Alfven waves become unstable under disturbed conditions when both ..sigma../sub p/ and V/sub 0y/ are enhanced. The resulting unstable Alfven waves can contribute to the Pi pulsations observed during substorms.

• Research Organization: Geophysical Institute, Universityj of Alaska, Fairbanks, Alaska 99701
• OSTI ID: 5098587
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:A5; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
EARTH ATMOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HYDROMAGNETIC WAVES
INSTABILITY GROWTH RATES
MAGNETOSPHERE
ONE-DIMENSIONAL CALCULATIONS
PHYSICAL PROPERTIES
PLASMA SHEET
PULSATIONS
WAVE PROPAGATION