Electron properties of high‐speed solar wind from polar coronal holes obtained by Ulysses thermal noise spectroscopy: Not so dense, not so hot
Open Access
- 1 October 2008
- journal article
- space sciences
- Published by American Geophysical Union (AGU) in Geophysical Research Letters
- Vol. 35 (19)
Abstract
We present radio observations of Ulysses' third fast latitude scan near the 2007 solar activity minimum of cycle 23. We deduce in situ measurements of the electron density and temperature using the method of quasi‐thermal noise spectroscopy. We study the large‐scale properties of the fast solar wind coming from polar coronal holes and compare our results to those obtained during Ulysses' first fast scan in 1994–1995 near the minimum of cycle 22. The fast solar wind in both hemispheres is less dense and cooler by about 19% and 13% respectively, as compared to the last solar minimum.Keywords
This publication has 20 references indexed in Scilit:
- Long-Term Changes of Polar Activity of the SunSolar Physics, 2004
- Solar Wind Electron Parameters from Ulysses/URAP Quasi-Thermal Noise Measurements at Solar MaximumSolar Physics, 2004
- Large-scale structure of the polar solar wind at solar maximum: ULYSSES/URAP observationsAIP Conference Proceedings, 2003
- Solar cycle changes in coronal holes and space weather cyclesJournal of Geophysical Research, 2002
- Ulysses' second fast‐latitude scan: Complexity near solar maximum and the reformation of polar coronal holesGeophysical Research Letters, 2002
- Solar wind plasma parameters on Ulysses: Detailed comparison between the URAP and SWOOPS experimentsJournal of Geophysical Research, 2001
- Solar wind observations over Ulysses' first full polar orbitJournal of Geophysical Research, 2000
- Quasi‐thermal noise in a drifting plasma: Theory and application to solar wind diagnostic on UlyssesJournal of Geophysical Research, 1999
- High-speed solar wind from Ulysses measurements and comparison with exospheric models1999
- Solar wind radial and latitudinal structure: Electron density and core temperature from Ulysses thermal noise spectroscopyJournal of Geophysical Research, 1998