Search Publications

Weaker solar wind from the polar coronal holes and the whole Sun

McComas, D. J.; Goldstein, B. E.; Schwadron, N. A. +4 more

Observations of solar wind from both large polar coronal holes (PCHs) during Ulysses' third orbit showed that the fast solar wind was slightly slower, significantly less dense, cooler, and had less mass and momentum flux than during the previous solar minimum (first) orbit. In addition, while much more variable, measurements in the slower, in-ecli…

Decrease in heliospheric magnetic flux in this solar minimum: Recent Ulysses magnetic field observations

Smith, Edward J.; Balogh, Andre

The Ulysses spacecraft has traveled from the solar equator at 1.3 and 5.3 AU to above the polar caps at 2.2 AU three times during the last 17 years and has provided measurements of the solar-heliospheric magnetic field. The open magnetic flux, i.e., the radial component, B_R, multiplied by the square of the radial distance, r, is indepen…

Electron properties of high-speed solar wind from polar coronal holes obtained by Ulysses thermal noise spectroscopy: Not so dense, not so hot

McComas, D. J.; Issautier, K.; MacDowall, R. J. +4 more

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 …

Origin of Jovian hiss in the extended Io torus

Horne, Richard B.; Thorne, Richard M.; Wang, Kaiti

Plasma wave observations on Voyager, Ulysses, and Galileo have shown that whistler-mode hiss at frequencies below one kHz is continuously present in the extended Io torus of Jupiter. Cyclotron resonant energies at frequencies below 1 kHz are extremely high (typically > MeV), and the Jovian resonant electron flux is too low to cause significant …