Studies of the origin and propagation of coronal mass ejections and of the behavior of the solar magnetic field
This thesis describes several studies of fundamental questions relating to the nature of coronal mass ejections (CMEs) and the solar magnetic field. First, a comparison is made between CMEs and the slow solar wind and it is found that the composition of both are very similar, with CMEs being a more extreme version of the same plasma. This result provides support for the theory that the slow solar wind originates on closed loops, in a smaller version of CME closed loops [Fisk and Schwadron, 2001b]. The slow solar wind plasma is released by intermittent reconnection processes in the solar corona, in strong contrast to models and theories that discuss the slow solar wind as a time-stationary, homogeneous plasma. These reconnection processes have important consequences for solar and heliospheric physics, some of which are explored in detail. As CME loops expand into the heliosphere they should consequently increase the magnetic flux in the heliosphere, without an apparent theoretical limit. We utilize a theory of open magnetic field line reconnection processes as described in Fisk and Schwadron  to predict the rate at which CME field lines will reconnect and open into the heliosphere, with good agreement to the data. We further utilize these intermittent reconnection processes to describe a method by which two closed magnetic loops can reconnect with one another. We find that this reconnection provides enough energy to drive coronal loop heating. We finally discuss a very important practical aspect of CME research: there is no agreed upon set of in situ identifiers of CME plasma. The final study in this thesis investigates the relationships between new, state of the art, composition measurements and more traditional in situ CME signatures. It is found that no one single signature can be used to accurately identify all periods of CME ejecta. Rather, CME ejecta appears to consist of various individual signatures that come and go without a clear pattern as the CME passes the spacecraft. However, compositional signatures seem to be the most reliable in the sense that they almost always occur in conjunction with other, more traditional, identifiers.
- Pub Date:
- November 2002
- Physics: Astronomy and Astrophysics, Geophysics