Plasma production by means of discharge in a spherical cavity

The work is devoted to the study of plasma, appearing as a result of cumulation of shock wave with form close to spherical. The shock wave was obtained by triggering of fast discharge (dI/dt about 10(12) A/s) on inner surface of cavity, made from insulator. Spherical cavity with radius 4.5 mm was filled with Ar at 80 Pa. Inductive storage with semiconductive opening switch was used as a current driver. Spherical plasma with diameter about 1 mm, emitting in vacuum ultraviolet (vuv), was detected by means of pinhole measurements with time gated microchannel plate camera, starting about 50 ns from the beginning of the discharge. vuv spectra have shown the presence spectral lines of ArV-ArVIII ions, which gives the estimation of electron temperature as 30 eV. The plasma ball reveals no instabilities, keeps its characteristics and emits vuv radiation during 300 ns. After 600 ns from the beginning of the discharge plasma emits a flux of electrons with energies about 1 keV with temporal structure about 100 ns. (C) 2010 American Institute of Physics. [doi:10.1063/1.3393769]