Research Interests:

Space physics, the space plasma physics of the solar wind's interaction with the Earth's magnetic field, auroral particle acceleration.

Space plasma physics is a study of electrodynamic phenomena in space, specifically a study of waves and charged particles in space and their interaction. We study these phenomena in order to understand the physics of natural plasmas. This is important in astrophysics since much of the known matter in the universe exists in the plasma state.

Our experimental research program consists of charged particle and wave measurements made in space at altitudes between a few hundred and 1,200 km altitude aboard sounding rocket flights. The rockets are flown through and over displays of the aurora at high latitudes. Sounding rocket flights have an advantage over orbiting satellites in that higher time resolution measurements can be made because of the lower velocity of the rocket payload as compared with orbital satellites and because we can use much higher telemetry rates to transmit the data back to the ground. In addition to the in situ rocket measurements, we study global electrodynamics using ground sensors capable of measuring very small magnetic field fluctuations of magnetohydrodynamic waves propagating in the Earth's magnetic field. These sensors are located in the Antarctic and the Arctic where background noise is very low and where the role of waves in the coupling of solar wind energy (the expansion of the solar atmosphere past the Earth) into the Earth's environment can be studied.

We have recently come to appreciate the importance that the plasma of the Earth's ionosphere at altitudes of a few hundred kilometers has in the electrodynamics of the Earth-solar wind system. Much of the mass trapped in the Earth's magnetic field (the Van Allen trapped radiation) comes from the ionosphere. Our recent rocket flights have made great progress in identifying the process by which ionospheric oxygen and hydrogen ions gain sufficient energy to overcome gravity and escape into space.

Our research support is through the National Science Foundation and NASA, and our research involves collaboration with scientists from Cornell University, the University of Minnesota, Dartmouth College, Augsburg College, and NASA Goddard Flight Center. Our graduate students receive the unique and exciting opportunity to actually train in building an experiment for space flight. With this experience, they readily land positions in industrial or government labs, or at universities after completion of their Ph.D.