Department of Astronomy Center for Radiophysics & Space Research

Plasma Astrophysics Group

The group’s main effort has been focused on developing detailed physical models of astrophysical environments where both rotation and ordered and/or chaotic magnetic field are important. These include the origin of astrophysical jets from magnetized accretion disks, the accretion of plasma to rotating magnetized stars. These problems are unavoidably complicated in that they involve calculations of multi-dimensional magnetohydrodynamic flows.

Estimates of the filling fraction for ionized particles in the interstellar and intergalactic medium range from a few percent to 100 percent. As shown by Earth's ionosphere where the ionization fraction can be less than one percent, plasma processes can be important even for very low filling fraction. Plasmas are a combination of neutrals, ions, electrons and fields that have conductive and collective effects and where interparticle dynamics is not dominated simply by binary collisions. This condition applies for most astrophysical systems. Even though space plasmas usually maintain quasi-neutrality to within less than about 1 part per million, there can still be substantial currents, convection, plasma flows, plasma waves and shocks and other plasma effects that interconnect plasmas over vast expanse as demonstrated by direct measurements of solar system space plasmas. Radio jets, interstellar shocks, stellar systems (especially neutron stars), and many astrophysical phenomena now appear to involve important plasma effects. Plasma astrophysics is the cutting edge of 21st century astrophysics and cosmology studies.

 

Professor Richard Lovelace

Sr. Research Associate Marina Romanova