OPTICAL SPECTROSCOPY TECHNIQUES - QSPA PLASMA FLOWS ANALYSIS

The parameters of the plasma flows generated by the P-50 and Kh-50 qua si-stationary plasma accelerators (QSPA) were measured. These paramete rs comprised the plasma density, velocity, and temperature. At the P-5 0 QSPA the measurements were carried out inside the hollow cathode, in the vicinity of the compression zone, and at the accelerator output. The accelerator chamber could be filled with the H-2, N2, Ar, and He g ases. Time-resolved profiles of the electron density n(e), excited-sta te atom density n(alpha), and ground-level atom density no were obtain ed. The plasma flow velocity and temperature were estimated. A fairly good agreement was found between parameters measured with different me thods. The experimental plasma flow velocity dependence upon the gas a tomic weight was corroborated by theory. At the Kh-50 machine we have measured the time-resolved plasma density profiles at different distan ces from the QSPA output. The density decayed from 2 - 3 x 10(16) to 3 - 4 x 10(15) cm-3 over a 70 cm distance from the accelerator output. The maximal recorded plasma flow velocity was 3 - 4 x 10(7) cm/s.