Expansion Characteristics of Plasma Generated by Electrically Exploding Single Aluminum Wire in High Vacuum

In this paper, the expansion characteristics of the plasma generated by electrically exploding single aluminum wire are studied through imaging spectra of plasma self-emission. Energy deposition in 40 $\mu{\rm m}$ and 100 $\mu{\rm m}$ exploding aluminum wires with two different rates of increase of current is presented and discussed. Imaging spectra with radius-resolved distribution in a wavelength range of 284 to 415 nm are used to study the composition and expansion rate of specific spectral lines in the explosion plasma. The plasma is symmetrical about its axis and mainly consists of AL I, Al II, and Al III. The expansion rates of intensities of some spectral lines in the plasma are determined by the specific energy deposited into the wire up to the voltage collapse. High current rate and large radius of the wire are helpful to suppress the plasma around the wire and the shunting of the current that causes the decrease of the deposited specific energy.