Possibility of Using the 140 GHz Frequency for ECR Plasma Heating in the T-15MD Tokamak

Kirneva, N.; Borshchegovskii, A. A.; Kuyanov, A. Yu.; Pimenov, I. S.; Roi, I. N.

doi:10.1134/s1063778822070067

Cited by 1 publication

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Radio-frequency (RF) plasma heating and current driving systems can be utilized for plasma start-up. The electron cyclotron resonance heating (ECRH), which was employed as one of the main heating systems in CDX-U [13], WT-3 [14], DIII-D [15], JT-60U [16], T-10 [17,18], TCV [19], W7-AS [20],W7-X [21], LHD [22], and in several STs (e.g. TST-2 [23], LATE [24], and QUEST [25]).…”

Section: Introductionmentioning

confidence: 99%

Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST

Kojima¹,

Hanada²,

Idei³

et al. 2021

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Noninductive plasma current start-up using 2nd harmonic electron cyclotron resonance heating (ECRH) with oblique radio frequency (RF) injection is demonstrated in a Q-shu University experiment with steady-state spherical tokamak. A strong transition was observed in the heating and plasma current ramp-up. The initial bulk electron heating regime exhibits T ebulk ∼ 140 eV and no hard x-ray (HXR) emission with a low I p of ∼15 kA; it abruptly transitions to a regime that exhibits a low T ebulk of ∼10 eV and a strong HXR emission with a high I p of ∼50 kA. This behavior is distinctly different from that observed in previous fundamental ECRH experiments. The mechanism of the heating and current drive transition are investigated considering wave power absorption and plasma power balance. The results indicate that the transition is caused by the favorable heating of tail electrons where the RF power absorption at the 2nd harmonic increases nearly linearly with T etail , while the power transfer from the tail electrons to the bulk electrons decreases with 1/T etail 0.5 . This causes a rapid transition to a state with high T etail while reducing T ebulk towards colder ion temperature. The understanding of the transition mechanism helps to consider plasma current start-up using 2nd harmonic ECRH for tokamak reactors such as JT-60 SA and ITER.

show abstract