Roy B. Torbert
Space Plasma/Magnetospheric Physics
Joint appointment Physics
Director of SwRI-EOS
Ph.D., University of California, Berkeley
Space plasma physics; physics of magnetospheres, aurora, and early solar system formation.
Over 99 percent of the observable universe is in the plasma state, where all matter is hot ionized gas, and collective, electrodynamic processes dominate the dynamics of their motion. Although the physics of plasma fusion is very similar, the only chance to study directly the physics of low-density, astrophysical plasmas and how they interact with ambient magnetic fields, is via spacecraft flown into the neighborhood of the Earth, around planets, and in the local interplanetary medium. The Experimental Space Physics Group focuses on construction and analysis of instruments to measure the properties of both particles and fields in these regions.
Our group is providing an array of instruments in the large NASA program called the International Solar-Terrestrial Physics Program, including particle spectrometers far out into the solar wind, upstream of the Earth's magnetic cavity (or "magnetosphere"), around the moon, and possibly to a nearby comet; an array of spectrometers over the pole of the Earth investigating the acceleration of plasma in the aurora (the processes all thought to be the same as those in solar flares or in active stellar systems and galaxies); and a set of innovative sensors for determining the electric and magnetic fields in space using test electron beams on a joint program with NASA and the European Space Agency called Cluster, involving four identical spacecraft.
However, our sounding rocket program is where students learn the fundamentals of the space business: designing their own experimental instruments, supervising the construction and testing, participating in the launch campaign, and finally analyzing the data to contribute a new scientific result. One such result is the figure that shows ionization produced in an "active" experiment in the ionosphere where we sought to re-create plasma conditions in the early solar system where plasma physics might have a significant impact on how the planets evolved. Thus, we can study not only how plasmas work in their natural space environment, but also how they may act in far away places and at very different times.