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| Titel |
Evidence of ion-cyclotron resonance heating of solar wind alpha particles |
| VerfasserIn |
Eckart Marsch, Sofiane Bourouaine, Fritz Neubauer |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051046
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| Zusammenfassung |
| We show evidence for the ion-cyclotron-wave dissipation mechanism acting in
the solar wind plasma by use of Helios data. We find that the wave power of the
small-scale transverse waves within the inertial range correlates with both, the proton
temperature anisotropy, T-¥-T-¥, and the normalized differential speed, V αp-V A,
between alpha particles and protons. Furthermore, when this relative speed stays below
0.5, then the alpha-particle temperature anisotropy correlates positively with the
relative power of the transverse waves. However, if V αp-V A is larger than 0.6, then
the alpha-particle temperature anisotropy tends to decrease towards values below
unity, despite the presence of transverse waves with relatively large amplitudes. Our
findings are in good agreement with theoretical predictions of kinetic theory for the
resonant interaction of ions with Alfvén-cyclotron waves and for the resulting wave
dissipation. |
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