May 21, 2010, 12:00 pm - 1:00 pm

May 21, 2010, 12:00 pm - 1:00 pm

Why is the solar wind so fast and hot?

D. Aaron Roberts (Heliospheric Physics Laboratory)

It has been known for many decades that the solar corona is orders of magnitude hotter than the photosphere, and that even with such a high temperature, thermal pressure is not enough for the corona to produce high-speed wind streams. It is likely that nonthermal mechanisms are needed. The two logical places to look are to waves and turbulence (in the fields) or to nonthermal distributions in the particles. This talk will briefly summarize why the wave/turbulence point of view very likely fails a number of observational and theoretical tests. If the answer is in the particle distributions, the main issue is the origin of required nonthermal features. New missions such as Solar Orbiter and Solar Probe will help greatly in resolving these issues.

IBEX, Voyager and the Edge of the Solar System

Eric Christian (Heliospheric Physics Laboratory)

In the last few years, we have seen a tremendous amount of new data about the interaction between our heliosphere and the local interstellar medium. However, these data have raised more questions than they have answered. The observations and their implications will be discussed.