Congratulations to Christina Migliore (Physics and Math ’18) for earning the Outstanding Undergraduate Poster Award at this year’s APS Division of Plasma Physics. The meeting was held in Milwaukee, Wisconsin October 23-27. Christina’s poster, “Properties of Large Amlitute Alfvén Waves in Magnetized Order Unity Beta laboratory Plasma.”
The research was carried out at UCLA where she recently completed a summer REU. Here is a short description on this research:
Alfven waves play an important role in magnetized plasmas in the laboratory, e.g. in fusion plasmas, and in space and astrophysical settings, e.g. in the solar wind. The Large Plasma Device (LAPD) at UCLA as been used to study the linear and nonlinear properties of these important waves, however in a low-beta plasma (beta ~ 10^-4). A new LaB6 cathode source has been installed in LAPD, allowing the generation of much higher pressure plasmas; with lowered magnetic field, magnetized plasmas with beta ~ 1 can be generated. Experiments were run to to vary the amplitude and frequency of the generated shear Alfvén waves at varying beta values. Dispersion and damping behavior of the waves were the primary focus of study. It was found that at higher beta values, the the dispersion relation that includes both frequency and finite perpendicular wavenumber corrections no longer describes data as well as it does at lower beta values. A dispersion relation by Lysak et al. 1996 that accounts for warm ions and which never been experimentally tested was shown to fit the higher beta data significantly better.