NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 1 of 60976
Energy transfer between energetic ring current H(+) and O(+) by electromagnetic ion cyclotron waves
External Online Source: doi:10.1029/94JA01007
Author and Affiliation:
Thorne, Richard M.(University of California, Los Angeles, CA, United States)
Horne, Richard B.(Natural Environment Research Council, Cambridge, England, United Kingdom)
Abstract: Electromagnetic ion cyclotron (EMIC) waves in the frequency range below the helium gyrofrequency can be excited in the equatorial region of the outer magnetosphere by cyclotron resonant instability with anisotropic ring current H(+) ions. As the unducted waves propagate to higher latitudes, the wave normal should become highly inclined to the ambient magnetic field. Under such conditions, wave energy can be absorbed by cyclotron resonant interactions with ambient O(+), leading to ion heating perpendicular to the ambient magnetic field. Resonant wave absorption peaks in the vicinity of the bi-ion frequency and the second harmonic of the O(+) gyrofrequrency. This absorption should mainly occur at latitudes between 10 deg and 30 deg along auroral field lines (L is greater than or equal to 7) in the postnoon sector. The concomitant ion heating perpendicular to the ambient magnetic field can contribute to the isotropization and geomagnetic trapping of collapsed O(+) ion conics (or beams) that originate from a low-altitude ionospheric source region. During geomagnetic storms when the O(+) content of the magnetosphere is significantly enhanced, the absorption of EMIC waves should become more efficient, and it may contribute to the observed acceleration of O(+) ions of ionospheric origin up to ring current energies.
Publication Date: Sep 01, 1994
Document ID:
19950057060
(Acquired Dec 28, 1995)
Accession Number: 95A88659
Subject Category: GEOPHYSICS
Document Type: Journal Article
Publication Information: Journal of Geophysical Research; p. p. 17,275-17,282; (ISSN 0148-0227); 99; A9
Publisher Information: United States
Contract/Grant/Task Num: NSF ATM-93-13158; NAGW-3476
Financial Sponsor: NASA; United States
Organization Source: NASA; Washington, DC, United States
Description: 8p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ELECTROMAGNETISM; ENERGY TRANSFER; HYDROGEN IONS; ION CYCLOTRON RADIATION; OXYGEN IONS; RING CURRENTS; EMISSION SPECTRA; GYROFREQUENCY; MAGNETIC FIELDS; MAGNETOSPHERIC INSTABILITY; WAVE PROPAGATION
Imprint And Other Notes: Journal of Geophysical Research vol. 99, no. A9 p. 17,275-17,282 September 1, 1994
Miscellaneous Notes: Research supported by NATO
Availability Source: Other Sources
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: August 19, 2011
Contact Us