Plasma Diagnostics of the Interstellar Medium with Radio Astronomy

Understand

We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM).

• The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio galaxies), as well as Galactic sources, primarily pulsars.
• The polarized synchrotron radiation of the Galactic non-thermal radiation also serves to probe the ISM, including space between the emitting regions and the solar system.
• Radio propagation measurements provide unique information on turbulence in the ISM as well as the mean plasma properties such as density and magnetic field strength.