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Title: Universal time control of AKR: Earth is a spin-modulated variable radio source
Authors: Morioka, Akira
Miyoshi, Yoshizumi
Kurita, Satoshi  kyouindb  KAKEN_id  orcid (unconfirmed)
Kasaba, Yasumasa
Angelopoulos, Vassilis
Misawa, Hiroaki
Kojima, Hirotsugu  kyouindb  KAKEN_id
McFadden, James P.
Keywords: AKR frequency variation
UT control
Variable radio source
spin modulation
Issue Date: Mar-2013
Publisher: American Geophysical Union
Journal title: Journal of Geophysical Research: Space Physics
Volume: 118
Issue: 3
Start page: 1123
End page: 1131
Abstract: Auroral kilometric radiation (AKR) is known to be transient emissions generated by rapidly accelerated electrons together with sudden auroral activation in the polar magnetosphere. In contrast, the characteristics and relationship with the auroral acceleration of rather continuous AKR emissions are not well understood. We examine the emission using long-term data and report that the continuous AKR emission frequency changes with universal time (UT) as the Earth rotates, indicating that the Earth is a spin-modulated variable radio source. The observed UT variation of AKR frequency means that the acceleration altitude changes periodically with planetary rotation. The observations indicate that the diurnal wobble of the tilted geomagnetic field in the solar wind flow alters the magnetosphere-ionosphere (M-I) coupling state in the polar magnetosphere, giving rise to periodic variation of auroral particle acceleration altitude. These observations of planetary radio wave properties provide insight into the physics of planetary particle acceleration.
Rights: ©2013. American Geophysical Union.
DOI(Published Version): 10.1002/jgra.50180
Appears in Collections:Journal Articles

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