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Solar cycle variations in the electron heat flux: Ulysses observations
Author(s) -
Scime Earl E.,
Littleton J. E.,
Gary S. Peter,
Skoug Ruth,
Lin Naiguo
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl012925
Subject(s) - solar wind , physics , heat flux , solar cycle , atmospheric sciences , whistler , solar maximum , coronal mass ejection , flux (metallurgy) , solar minimum , geophysics , plasma , heat transfer , mechanics , materials science , metallurgy , quantum mechanics
Solar wind observations by the Ulysses spacecraft now include nearly ten years of continuous ion and electron measurements. In this study, we report detailed measurements of the electron heat flux in the solar wind. In particular, we examine the heat flux measurements for long‐term correlations with wave activity and solar wind speed. We find that the average heat flux, when scaled by R 2.9 to account for variations due to distance from the Sun, is constant and independent of heliographic latitude or solar cycle. We find that during both solar maximum and solar minimum, there is no significant correlation between the magnitude of the electron heat flux and the solar wind speed. Comparison of the electron heat flux data with wave activity indicates that the whistler heat flux instability does not play an important role in limiting the solar wind heat flux.