"Theory and Observation of High Energy Particles in Space"

Nasser Barghouty

Physics Department
Roanoke College
Salem, Va

Abstract

Near-earth space environment is rich in energetic particles of various energies and intensities. High-altitude balloon-borne and space-borne instruments detect electrons, protons, and heavier nuclei and ions over a vast energy range; from thermal to ultra-relativistic. Some of these particle intensities vary periodically in time with the solar cycle, others are of random nature.

Sorted according to their energy and temporal variation, the particles can be divided into four distinct populations: (i) particles that make up the solar wind, (ii) particles that are ejected by our Sun in spectacular, random events, (iii) particles that wander about and into our solar neighborhood from the surrounding interstellar space, and (iv) particles that are ejected by supernovae throughout our galaxy and, perhaps, from beyond. This talk is an eclectic tour of some space-based observations of these particles, notions and models describing the origin, acceleration, and transport, as well as some practical applications stemming from, and indeed requiring, their systematic study. Because they are the most difficult to predict, emphasis is on the second population of particles, and on the third because of their more recent discovery and the current controversies surrounding their origin and acceleration.


Dr. Barghouty currently holds the Brian H. Thornhill Professor of Physics position at Roanoke College in Salem, Virginia. He has been a visiting scholar at the Naval Research Laboratory in Washington, DC, the University or Arizona, and the California Institute of Technology. He is the author and/or co-author of more than thirty research papers on space, nuclear, and radiation physics. His current interests include theory and modeling of stochastic transport and acceleration processes in space plasmas. He is the recipient of a number of awards recognizing his research work as well as mentorship of students and young researchers. He holds a B.S. degree in electrical engineering from San Jose State University, San Jose, California, and M.A. and Ph.D. degrees in nuclear physics from Kent State University, Kent, Ohio.