AGU member since 1984. Associate professor in the Department of Physics and the Space Science Center at University of New Hampshire, Durham. Major interests are in the impact of heavy ions on dynamics of the magnetosphere, particularly in the ring current and magnetotail. Also very interested in space instrumentation to measure ion composition; involved in developing instruments for CLUSTER, FAST, Equator-S, ACE, and STEREO. B.S. in physics from Harvey Mudd College. M.S., 1983, and Ph.D., 1987, from University of Maryland. Prior to coming to UNH, was a research associate at University of Maryland, 1987–1988, and a visiting scientist at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, in 1988–1990. Joined the University of New Hampshire in 1990, first as a research scientist, then as research assistant and research associate professor. Became an associate professor in 2002. Author or coauthor of 138 publications, 71 in AGU journals. Member of NASA's Sun-Earth Connections 2000–2025 Roadmap Committee and the Heliophysics Lunar Science subpanel.