Parameters of the plasma produced at the surface of a ferroelectric cathode by different driving pulses

Abstract

Spectroscopic investigations of the properties of a plasma produced by a ferroelectric-plasma source are presented. The electron plasma density, the electron and ion temperature, and the density of desorbed neutrals near the ferroelectric surface are determined from spectral line intensities and profiles. Three different methods of surface plasma formation are analyzed using a simplified model for the plasma production. The model predicts the total amount of charge in the plasma to be proportional to the dielectric constant of the ferroelectric material. Also, the model shows a strong dependence of the plasma parameters on the resistivity of the plasma transition layer. A maximal plasma density of ∼1015cm−3 is achieved when the electrons that were attached by the driving field to the ferroelectric surface are released from the surface owing to driving pulse sharp decay and ionized heavy atoms desorbed from the ferroelectric.

Non-disturbing measurements of hollow-anode plasma parameters

“…It can be seen that in figure 3(a) (case (a)) the spectral line is not broadened or shifted. Indeed, in case (a) at τ d = 15 μs and d = 3 mm, the plasma density is not more than 10 11 cm −3 [7,10,11,15]. Therefore, the image of the scattered light by the plasma electrons was significantly weaker than the maximal achievable sensitivity of our experimental set-up.…”

“…The plasma density was estimated from the measurements of the Stark broadening of the H α and H β spectral lines using the algorithm described in [15]. These measurements were performed during the HA discharge with τ d = 5 μs and a frame duration of 10 μs.…”

Electron Emission from Barium Strontium Titanate Ceramics

“…At this high electric field, an explosive emission will certainly occur. [15][16][17] Firstly, this high electric field lowers the potential barrier between the material and vacuum, allowing the field emission to occur, i.e., the electrons from the lattice overcome the high surface potential and emit to the vacuum. Then, the explosive emission plasma dominates the emis-sion process.…”

“…Consequently, surface plasma is generated. [14][15][16][17] When there is no extraction potential, the surface plasma will expand to the strip electrode and the bare surface of the ferroelectric. The plasma near the strip electrode has the same potential as the grounded strip electrode.…”

Strong electron and ion emissions induced by a pyroelectric crystal

“…18 Although there were debates on the mechanisms for the strong FEE, it is generally believed to be a plasma-assisted electron emission. [15][16][17][18][19][20] When a driving voltage pulse is applied to the rear (or front) electrode of the ferroelectric material, a tangential component as well as the normal component of the applied electron field is created. 21 points where metal, vacuum, and the ferroelectric material meet, the electric field is increased by a factor of e r , here e r is the relative dielectric constant of the dielectric material, 22 as a result field electron emission occurs at the triple junctions.…”