The spatial-temporal distribution of the electron density and temperature in nanosecond pulsed discharge plasma measured by laser Thomson scattering

The spatial-temporal distribution of the electron temperature (T-e) and density (n(e)) in a nanosecond pulsed discharge (NPD) argon plasma with a ball-to-plate electrode configuration at 2 x 10(3) Pa has been measured by Laser Thomson Scattering (LTS). The peak voltage between two electrodes is 1520 V and the current is 3 A when the ball-like electrode is connected to the negative high voltage. The results indicate that it is possible to enhance the electron density of the plasma discharge using the rising edge of pulse voltage. The measured plasma parameters: T-e decreases exponentially from 1.75 eV to 0.1 eV and n(e) increases rapidly to 3.94 x 10(20) m(-3) from 15 ns to 115 ns then decreases to 1.17 x 10(19) m(-3). In the discharge with cylindrical geometric symmetry, T-e increases from ball to plate, while n(e) is opposite. In the r-direction, both T-e and n(e) decrease from central to edge at 3.4 mm. Value of n(e) varies by 20 times from maximum to minimum and T-e is only about 1.5 times.