Plasma Spectral Characteristics of Single Aluminum Wire Electrically Exploded in High Vacuum

The wire-array Z-pinch has been regarded as one of the most competitive technological approaches to realize the Inertial Confinement Fusion. The exploding-wire stage, which provides the initial conditions for the wire-array Z-pinch, makes a significant influence on the subsequent implosion process. Using a 1-kA nanosecond negative pulse current source, conditions of plasmas generated by current-driven explosions of single aluminum wires in vacuum is studied. The self-emission spectrum of aluminum (Al) wire explosion is investigated using imaging spectrometer with an integrating time of 5 ns. In the spectrum, the characteristic spectral lines of carbon, hydrogen and aluminum ions of different valence states are identified. The electron temperature of the plasma is estimated by the Boltzmann Plot of isolated lines of Al-III with wavelengths of 361.34nm, 415.77nm and 453.98nm. The deconvolution of the waveform of self-emission spectrum is carried out to separate the Doppler Broadening and the Stark Broadening, and then the Stark Broadening is used to calculate electron density. The results show that the electron temperature in the plasma is about 3.47ev and the electron density is about $8.87 \times 10 ^{18} cm ^{-3}$. Besides, constituents of the exploding products are analyzed by the calculation based on non-ideal Saha equation. The distribution of Al ions of different valence states and Al neutral particles are calculated according to the given temperature and density of plasma.