Laboratory astrophysics: the SSX plasma wind tunnel at Swarthmore
Turbulent fluctuations in conventional fluids like air or water seem to have a universal character. Laboratory measurements of statistical turbulence in a one-meter wind tunnel, or in a 100-meter tidal basin, or 10 km atmospheric structures seem to be the same. It is not known whether plasma turbulence is universal in the same way. The Sun launches a turbulent stream of high velocity plasma (called the solar wind) with embedded magnetic fields into interplanetary space at about 400 km/s. Statistical properties of the solar wind have been studied with satellites for decades, and much is known about fluctuations and correlations in the velocity, density, and magnetic fields.
In this talk, I'll discuss measurements in a high velocity plasma wind tunnel at Swarthmore College. The SSX MHD wind tunnel features flow speeds up to 100 km/s, magnetic field of 0.5 T, and temperatures of nearly a million Kelvin. Comparisons to measurements in the solar wind will be made. We are preparing an experiment to study high-velocity of collisions of plasmas, as might happen in stellar atmospheres.