Understanding electron transport in a laboratory plasma of LVPD, a major cause considered responsible for the plasma loss in fusion devices. The electron heat transport in fusion devices is critical and the information available is limited. The information present is primarily based on the theoretical and numerical predictions. These predictions are suggestive that the electron temperature gradient (ETG) driven turbulence is the major source of plasma loss but it remains unexplored because of extremely small scale length nature of instability and no direct access to measure in tokamaks
Exciting unambiguous ETG, studying its threshold, beta scaling of plasma transport, effect of magnetic shear on ETG and understanding non linear features like Zonal flows and Streamers are various exciting problems which needs dedicated effort. We believe that unfolding these physics issues in LVPD will greatly contribute to fusion fraternity because of their relevance to fusion plasma.
The device like LVPD plays undoubtedly a significant role in carrying out such studies. A major contribution made of LVPD is the invention of a large 2m diameter electron energy filter(EEF), perhaps the largest available today, for producing plasma suitable for ETG study. We have produced plasma devoid of energetic electrons and excited unambiguous ETG turbulence in LVPD [Physical Review Letters, 108, 255007 (2012)]with leverage of controlling temperature gradient scale length between 50-600 cm
Another important physics program running in LVPD is on understanding the filter plasma. This comprises of study of trapped particles, energetic particle diffusion across magnetic field and associated drifts, excitation of whistler and lower hybrid kind of instabilities associated with energetic electrons, instabilities associated with electron temperature anisotropy and study of wave – particle interaction in the belt region.
The energetic belt region in LVPD mimics the Van Allen belt regions of earths magnetosphere. This possibility is under investigation.