Spectroscopic measurements of the electron density in a current sheet produced under high-pressure helium filling

The results are presented from the measurements of the temporal evolution of the electron density in a current sheet produced under high-pressure helium filling in a two-dimensional magnetic field with a zero line. The electron density is determined mainly from the broadening of the spectral lines of helium atoms and ions and also the H-alpha line, which are emitted from the different regions of the current-sheet plasma. The HeII P-alpha line is used to measure the plasma density at the midplane of the current sheet, where the maximum density attains N-e approximate to 10(17) cm(-3). The minimum density, which is an order of magnitude lower, characterizes the background plasma surrounding the sheet.