More information on FAST, as well as examples of magnetic fields data can be found on the IGPP/UCLA FAST web page.
As part of the SPDS efforts, we have also developed an interactive data server for the ISEE-1 and -2 magnetometer data.
The analysis of plasma waves in the Venus foreshock allows us to investigate the possible generation mechanisms for the waves. Through statistical studies of the distribution of the waves we find that Fast-Fermi acceleration, where solar wind electrons bounce off the bow-shock, which appears as a moving mirror in the solar wind frame, explains much of the features of the waves. We also find that shock curvature may play a role in limiting the amount of energy the electrons gain as they reflect of the shock. As such, then, the studies of waves in the Venus foreshock provide a laboratory for the investigation of shock acceleration and wave generation.
The second topic, the investigation of the interaction of the solar wind with an unmagnetized planet, was originally motivated by the observation of plasma waves near the ionopause of Venus. It was argued that these waves could supply heat to the ionosphere as they propagate to lower altitudes. However, some of our more recent work suggests that the waves are probably not a significant heat source for the ionosphere. Instead they appear to be involved in the coupling process between plasma of planetary origin and the solar wind. Whether the waves provide momentum coupling, or local heating, has yet to be determined. In our efforts to understand the wave morphology, we have found that the waves are observed in or near regions of field-aligned current. These field-aligned currents deflect the magnetosheath field from the ambient magnetosheath orientation to an orientation dictated by the hanging up of field lines as they penetrate the ionosphere and are mass-loaded.
Some of this research was presented in a poster paper at the Venus II Conference.
The last research topic in the area of Venus related work is the controversial one of whether or not the plasma waves observed on the nightside of Venus are due to planetary lightning. Our work over the last few years has provided a large body of evidence that the waves are indeed due to lightning. No individual piece of evidence is conclusive, but the evidence, when viewed as a whole, clearly supports the lightning interpretation.
However it has recently been pointed out that the heating due to collisional Joule dissipation at low altitudes could be very large within the Venus ionosphere. It has been argued that this alone precludes a lightning source for the waves. We are currently developing models to investigate this point further. Our initial conclusion is that some heating might occur, but it is not significant.
Some of this work was presented in poster papers at the 1994 Fall AGU Meeting and the 1995 Spring AGU Meeting.
UCLA/IGPP Space Physics Center home page Bob Strangeway's home page
Last updated: February 8th, 2000