On electron temperature rise in divertor relevant recombining plasma along magnetic field line

Abstract

The rise of electron temperature along the magnetic field line was clearly observed in divertor relevant recombining plasma, even though there was no additional electron heating source. Electron temperature obtained at recombination front was approximately 0.5 eV, whereas it increased up to greater than 1 eV at downstream of recombination front. Although this temperature rise is likely common in detached or recombining plasmas, the mechanism has not been understood yet. This report provides a reasonable interpretation of temperature rise along the magnetic field line, for the first time: depletion of low energy electrons due to volumetric recombination leads to deformation of electron energy distribution, resulting in an apparent increase in electron temperature. Our experiment supports this interpretation in that the experimentally observed electron temperature showed good agreement with calculated effective electron temperature.

Structure of intermittent variation of floating potential in a converging field following a magnetic beach ECR plasma source

“…Cylindrical magnetized plasmas are widely used as simple well-defined targets for basic plasma physics experiments [1][2][3][4] as well as for divertor plasma simulating experiments. [5][6][7][8][9][10] Then converging magnetic field configuration is often adopted. 3,4,[7][8][9][10] This is because the field strength in the plasma source region is sometimes lower than that required for the test region due to the suitable range of magnetic field for each plasma production method.…”

“…[5][6][7][8][9][10] Then converging magnetic field configuration is often adopted. 3,4,[7][8][9][10] This is because the field strength in the plasma source region is sometimes lower than that required for the test region due to the suitable range of magnetic field for each plasma production method. 11) Measurement and control of temperature and density in the high field test region are important issues.…”