CER SEMINAR

An Effort to Investigate the Equations of State Applicable to a Mildly-Collisional Magnetized Plasma

Manjit Kaur, Swarthmore College, Pennsylvania
May 4, 2018, 11:00am - 12:00pm, SERF Room 232

ABSTRACT:

Measuring the equations of state of a compressed magnetized plasma is important both for advancing fusion experiments and understanding natural systems such as stellar winds. However, not much has been done in this regard. In this talk, I will present results from our recent experiments in which we have explored the thermodynamics of compressed magnetized plasmas1;2; we call these studies "magnetothermodynamics". In these experiments, we generate parcels of magnetized, relaxed plasma using a magnetized coaxial plasma gun located at one end of the linear device and observe their compression in a closed conducting boundary installed at the other end. Plasma parameters are measured during compression. The instances of ion heating during compression are identified by constructing a PV diagram using measured density, temperature, and volume of the magnetized plasma. The theoretically predicted MHD and double adiabatic (CGL) equations of state are compared to experimental measurements to estimate the adiabatic nature of the compressed plasma. Since our magnetized plasmas relax to an equilibrium described by magnetohydrodynamic3, one might expect their thermodynamics to be described by the corresponding equation of state. However, we find that the magnetohydrodynamic equation of state is not supported by our data. Our results are more consistent with the parallel CGL equation of state suggesting that these mildly collisional plasmas have most of their proton energy in the parallel direction to the magnetic field.
 
Work supported by DOE OFES and ARPA-E ALPHA programs.
 
1Kaur et. al., Phys. Rev. E. 97, 011202 (2018).
2Kaur et. al., J. Plasma. Phys. 84, 905840114 (2018).
3Gray et. al., Phys. Rev. Lett. 110, 085002 (2013).

BIO:

Manjit Kaur received her PhD degree in complex plasma physics from Institute for Plasma Research, India. During her PhD, she worked on the vertical levitation and rotation of micron sized dust particles and explored the cause of dust particle rotation experimentally and theoretically. After completion of her PhD, she joined Swarthmore College as a Post-doctoral research fellow in May 2016. Manjit’s research interests include experimental study of magnetohydrodynamic plasmas (especially force-free states), acceleration and compression of magnetized plasmas, thermodynamics of magnetized plasmas, turbulence, density and magnetic field correlations, magneto-inertial fusion, etc.