Bolometer measurements of ultra-low-q and reversed field pinch plasmas in REPUTE-1

Morimoto, Hiroshi; Kamada, Y.; Fujita, T.; Murakami, Yoshiki; Fuke, Yasutaka; Saito, K.; Nihei, Hitoshi; Morikawa, Junji; Yoshida, Zensho; Inoue, N.

doi:10.1088/0029-5515/29/7/010

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…The increase in plasma temperature after density pump-out is explained by such estimates related to the radiation barrier. A detailed measurement of the radiated power loss is discussed elsewhere [51]. The plasma parameters of ULQ discharges depend strongly on the wall condition.…”

Section: Density Pump-out and Radiation Barriermentioning

confidence: 99%

Recent results of ultra low q experiments in TORIUT-6 AND REPUTE-1

Kamada¹,

Fujita

Murakami

et al. 1989

Nucl. Fusion

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In REPUTE-1, the radiation barrier has been overcome and ion and electron temperatures of ⪅ 0.6 keV (Ti) and ⪅0.3 keV (Te) have been achieved at an electron density of (0.2–0.7) × 1020 m−3 and toroidal beta values of 12-18%. A resistivity anomaly due to m = l kink activity has been observed which may be connected with the peaked temperature profile and the rather broad current density profile. The plasma resistance is lower than that of reversed field pinch discharges in REPUTE-1 and decreases with increasing plasma current. In TORIUT-6, the effects of current ramp-up and carbonization of the first wall have been studied. A hollow current density profile, typical of ultra low q equilibria, is preserved which may be due to the skin current effect. The difference between current ramp-up discharges and standard discharges is the extended duration of the quiescent phase and the preservation of the position of the pitch minimum away from the axis in the ramp-up discharges. After carbonization, the duration of the quiescent phase increases and the plasma resistivity is reduced by 50%.

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Section: Density Pump-out and Radiation Barriermentioning

confidence: 99%

Recent results of ultra low q experiments in TORIUT-6 AND REPUTE-1

Kamada¹,

Fujita

Murakami

et al. 1989

Nucl. Fusion

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“…In deuterium plasmas with I p = 300 kA, time-of-flight (TOF) neutral particle energy analysis showed T ; = 250 eV, and soft X-ray analysis showed T e = 350 eV after density pump-out [20,21]; emission of neutrons was also observed [21]. Bolometer measurements indicated a reduction of the radiated power in high current ULQ plasmas with I/N > 1 x 10" 14 A-m [22]. Since the observed high ion temperatures cannot be explained by classical electron-ion collisions, some kind of ion heating mechanism must exist in ULQ plasmas as well as in RFP plasmas.…”

Section: Introductionmentioning

confidence: 99%

Anomalous ion heating in REPUTE-1 ultra-low q and reversed field pinch plasmas

Fujita¹,

Saito

Matsui

et al. 1991

Nucl. Fusion

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Measurements of ion and electron temperatures on REPUTE-1 ultra-low q (ULQ) and reversed field pinch (RFP) plasmas have revealed that the ion temperature is higher than the electron temperature and that the impurity ion temperature exceeds the hydrogen ion temperature. In ULQ plasmas the impurity ion temperature is correlated with the amplitude of the magnetic field fluctuations observed outside the plasma. A model on ion heating by fluctuations is found to explain the experimental results.

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“…The electron density r^ is typically of the order of 10 19 m" 3 (CO 2 laser interferometry). In the following data sets, highly radiative discharges with high filling pressure are excluded [14]. The ions are heated to several hundreds of eV through a direct heating mechanism [4,5,13,15,16].…”

mentioning

confidence: 99%

Experimental scaling of anomalous resistance in ultra-low q discharges

et al. 1991

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The resistance anomaly in ultra-low q (surface safety factor q(a) < 1) discharges has been studied experimentally. The effective resistance (loop voltage/plasma current) is much higher than the kinematic resistance calculated with the electron temperature. The effective resistance is inversely proportional to the applied toroidal magnetic field. This scaling applies universally to devices with different dimensions.

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Bolometer measurements of ultra-low-q and reversed field pinch plasmas in REPUTE-1

Cited by 5 publications

References 7 publications

Recent results of ultra low q experiments in TORIUT-6 AND REPUTE-1

Recent results of ultra low q experiments in TORIUT-6 AND REPUTE-1

Anomalous ion heating in REPUTE-1 ultra-low q and reversed field pinch plasmas

Experimental scaling of anomalous resistance in ultra-low q discharges

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