TY - GEN
T1 - Electron bernstein wave emission studies on the TJ-II stellarator
AU - Caughman, J. B.O.
AU - Rasmussen, D. A.
AU - Wilgen, J. B.
AU - Fernández, A.
AU - Cappa, A.
AU - Castejón, F.
PY - 2009
Y1 - 2009
N2 - Electron Bernstein Wave (EBW) heating is important for high-beta plasma experiments and will be used for heating over-dense plasmas on TJ-II. TJ-II is a medium sized Heliac operating at CIEMAT in Madrid, whose plasmas are created and heated by ECH via two 300 kW gyrotrons at second harmonic X-mode (53.2 GHz), with additional heating provided by two neutral beam injectors. Theoretical work has shown that the most suitable scheme for launching EBWs in TJ-II is O-X-B mode conversion, which has acceptable heating efficiency for central densities above 1.2 × 1019 m-3 [1]. A system based on a 28 GHz-100 ms diode gyrotron will be used to deliver 300 kW through a corrugated waveguide. The microwave-heating beam will be directed and focused by a steering mirror located inside the vacuum vessel. Prior to the heating experiments, measurement of the thermal EBW emission (EBE) from the plasma is being made to help determine the optimum launch angle for EBW mode conversion, and also to provide an indication of the electron temperature evolution in over-dense plasmas. A dual-polarized quad-ridged broadband horn is used to measure the EBW emission and polarization at 28 GHz. Initial measurements indicate that the emission in under-dense plasmas corresponds to oblique electron cyclotron emission (ECE) and then converts to EBE when the plasma becomes over-dense during neutral beam injection.
AB - Electron Bernstein Wave (EBW) heating is important for high-beta plasma experiments and will be used for heating over-dense plasmas on TJ-II. TJ-II is a medium sized Heliac operating at CIEMAT in Madrid, whose plasmas are created and heated by ECH via two 300 kW gyrotrons at second harmonic X-mode (53.2 GHz), with additional heating provided by two neutral beam injectors. Theoretical work has shown that the most suitable scheme for launching EBWs in TJ-II is O-X-B mode conversion, which has acceptable heating efficiency for central densities above 1.2 × 1019 m-3 [1]. A system based on a 28 GHz-100 ms diode gyrotron will be used to deliver 300 kW through a corrugated waveguide. The microwave-heating beam will be directed and focused by a steering mirror located inside the vacuum vessel. Prior to the heating experiments, measurement of the thermal EBW emission (EBE) from the plasma is being made to help determine the optimum launch angle for EBW mode conversion, and also to provide an indication of the electron temperature evolution in over-dense plasmas. A dual-polarized quad-ridged broadband horn is used to measure the EBW emission and polarization at 28 GHz. Initial measurements indicate that the emission in under-dense plasmas corresponds to oblique electron cyclotron emission (ECE) and then converts to EBE when the plasma becomes over-dense during neutral beam injection.
UR - http://www.scopus.com/inward/record.url?scp=84903835305&partnerID=8YFLogxK
U2 - 10.1142/9789812814647_0031
DO - 10.1142/9789812814647_0031
M3 - Conference contribution
AN - SCOPUS:84903835305
SN - 9812814639
SN - 9789812814630
T3 - Proceedings of the 15th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC-15
SP - 232
EP - 237
BT - Proceedings of the 15th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC-15
PB - World Scientific Publishing Co. Pte Ltd
T2 - 15th Joint Workshop on Electron Cyclotron Emission, ECE 2008 and Electron Cyclotron Heating, ECH 2008
Y2 - 10 March 2008 through 13 March 2008
ER -
