Research Interests

My primary interests are solar system physics, local interstellar medium, cosmology and astrophysics, and design and development of spacecraft instrumentation for plasma composition measurements. I also investigate physical processes in the Sun, the heliosphere, the local interstellar cloud, the magnetospheres of Earth and outer planets, and interactions between these systems. The composition in these systems, which is the primary focus of these studies, is obtained from direct observations of the elemental, isotopic and charge state abundance of the solar wind and supra-thermal ions with a new class of time-of-flight instruments (SWICS) flown on various NASA and ESA spacecraft including AMPTE, Voyagers, Ulysses, WIND, Geotail, and ACE. My recent work includes studies of the properties of the local interstellar medium, such as its magnetic field strength, density, and composition of its gas and plasma, and its interaction with the heliosphere. These studies use a new sensing technique based on observations of interstellar pickup ions discovered with SWICS on Ulysses in the inner heliosphere. For example, detailed measurements of pickup ions (created by ionization of interstellar gas well inside the orbit of Jupiter) have established the present day 3He/4He ratio, thus setting new limits on the amount of missing matter and galactic chemical evolution. Based on composition measurements of the solar wind, work is currently in progress to establish the chemical and isotopic abundance of the solar atmosphere and to determine the origin and acceleration of the solar wind.

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Primary Section

Section 16: Geophysics