TY - GEN
T1 - Oscillatory behavior of hollow grid cathode discharges
AU - Schrittwieser, Roman
AU - Teodorescu-Soare, Claudia Teodora
AU - Enescu, Florin
AU - Ionita, Codrina
AU - DImitriu, Dan Gheorghe
AU - Gurlui, Silviu
AU - Mazzanti, Federico
AU - Irimiciuc, Stefan Andrei
AU - Hodoroaba, Bianca
AU - O'Hara, Turlough
AU - Vasilovici, Ovidiu
AU - Amarandi, Lidia
N1 - Publisher Copyright:
© 2019 IEEE.
PY - 2019/9
Y1 - 2019/9
N2 - Multiple complex space-charge structures in unmagnetized low-temperature plasmas arise from ionization phenomena near additional negatively or positively biased electrodes or due to local constraints. Because of their usually spherical form, such structures are called fireballs. If they appear inside hollow grids, they are called inverted fireballs or plasma bubbles. The temporal evolution of such structures is often accompanied by strong plasma instabilities. The dynamics of complex space-charge structures have been investigated by using single spherical grid cathode with an orifice. Langmuir probe and optical emission spectroscopy were used to diagnose the structures. Measurements delivered the axial profiles of the plasma potential, electron temperature and density, and the densities of excited atoms and ions, that confirmed the formation of a fireball in the region near the orifice (also evidenced by visual observation). Inside the grid, a plasma bubble has developed, with a high ion density inside due to the hollow cathode effect. Information on the nonlinear dynamics of the complex space charge structures was obtained from the analysis of the oscillations of the discharge current.
AB - Multiple complex space-charge structures in unmagnetized low-temperature plasmas arise from ionization phenomena near additional negatively or positively biased electrodes or due to local constraints. Because of their usually spherical form, such structures are called fireballs. If they appear inside hollow grids, they are called inverted fireballs or plasma bubbles. The temporal evolution of such structures is often accompanied by strong plasma instabilities. The dynamics of complex space-charge structures have been investigated by using single spherical grid cathode with an orifice. Langmuir probe and optical emission spectroscopy were used to diagnose the structures. Measurements delivered the axial profiles of the plasma potential, electron temperature and density, and the densities of excited atoms and ions, that confirmed the formation of a fireball in the region near the orifice (also evidenced by visual observation). Inside the grid, a plasma bubble has developed, with a high ion density inside due to the hollow cathode effect. Information on the nonlinear dynamics of the complex space charge structures was obtained from the analysis of the oscillations of the discharge current.
KW - Fireball
KW - Hollow cathode
KW - Oscillations
KW - Plasma bubble
UR - http://www.scopus.com/inward/record.url?scp=85074955753&partnerID=8YFLogxK
U2 - 10.1109/ICEAA.2019.8879126
DO - 10.1109/ICEAA.2019.8879126
M3 - Conference contribution
AN - SCOPUS:85074955753
T3 - Proceedings of the 2019 21st International Conference on Electromagnetics in Advanced Applications, ICEAA 2019
SP - 1359
EP - 1362
BT - Proceedings of the 2019 21st International Conference on Electromagnetics in Advanced Applications, ICEAA 2019
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 21st International Conference on Electromagnetics in Advanced Applications, ICEAA 2019
Y2 - 9 September 2019 through 13 September 2019
ER -