|M.Sc Student||Vekselman Vladislav|
|Subject||Thomson Scattering Measurements of the Plasma Parameters in|
a Hollow-Anode with Ferroelectric Plasma Source
|Department||Department of Physics||Supervisors||Professor Yakov Krasik|
|Professor Emeritus Joshua Felsteiner|
|Full Thesis text|
Plasma evolution was investigated during the operation of a hollow-anode (HA) with an incorporated ferroelectric plasma source (FPS). This FPS-assisted HA has recently been introduced as a reliable and reproducible electron source for pulsed high-current electron beam generation. Thomson scattering of a pulsed Nd-YAG laser beam was applied to study the plasma parameters during the FPS-assisted HA operation. This diagnostics allows one to obtain the spatial and time resolved plasma electron temperature and density at the vicinity of the FPS, avoiding difficulties related to spectroscopic measurements in the case of unknown electron energy distribution. It was found that the electron density and energy of the plasma at the vicinity of the FPS are ~1015 cm−3 and ≤ 5 eV, respectively, and the density of the hollow anode bulk plasma is ~6×1013 cm−3. Applying an accelerating pulse for electron extraction from the bulk plasma leads to an increase in the electron density and energy of the ferroelectric surface plasma up to 6×1016 cm−3 and ≤ 20 eV, respectively. Comparison of the Thomson scattering data with more conventional visible spectroscopy measurements is offered as well. It was shown that the self-sustained formation of the plasma at the surface of the FPS allows continuous (of several microseconds) operation of the HA. In addition, it was found that the plasma formation on the ferroelectric surface is accompanied by intense generation of micro-particles having velocities up to 3´105 cm/s.