42GHz ECRH assisted Plasma Breakdown in tokamak SST-1

Shukla, B. K.; Pradhan, Subrata; Patel, Paresh; Babu, Rajan; Patel, Jatin; Patel, Harshida; Dhorajia, Pragnesh; Tanna, V. L.; Atrey, P.K.; Manchanda, R.; Gupta, Manoj Kumar; Joisa, S.; Gupta, C.N.; Danial, Raju; Singh, Prashant Kumar; Jha, Ratneshwar; Bora, D.

doi:10.1051/epjconf/20158702008

Cited by 7 publications

(2 citation statements)

References 12 publications

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“…This system can deliver maximum 200kW ECRH power and considering 20% transmission loss, only 160kW ECRH will be available for ECRH experiments and this power is not sufficient for plasma start-up at second harmonic (1.5T) and ECR heating also demands higher power. This has been experimentally observed in SST-1 with 42GHz ECRH system [7]. At fundamental harmonic (1.5T operation) 150kW ECRH power is sufficient for plasma breakdown while for second harmonic breakdown (0.75T operation), more than 250kW ECRH power was required for reliable breakdown and plasma start-up.…”

Section: Upgradation Plan Of Ecrh System On Sst-1mentioning

confidence: 75%

ECRH experiments on Tokamaks SST-1 & Aditya-U and ECRH upgradation plan for SST-1

Shukla

Patel²,

Patel³

et al. 2023

EPJ Web Conf.

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A 42GHz-500kW ECRH system [1-6] is used to carry out various experiments related to plasma breakdown and ECR heating on tokamaks SST-1 and Aditya-U. The system has been upgraded with new anode modulator power supply to launch two ECRH pulses to carry out breakdown and heating simultaneously. In SST-1, ECRH system is used routinely for plasma breakdown at fundamental harmonic, approximately 150kW power is launched for 70ms to 150ms duration and consistent plasma start-up is achieved in SST-1. In the recent experiments, second EC pulse is also launched at the plasma flat-top to heat the plasma, some heating signatures are seen but more experiments will be carried out to confirm the plasma heating with ECRH. In Aditya-U tokamak, simultaneous plasma breakdown and heating experiments are carried out successfully [2]. In the first pulse around 100kW power in fundamental O-mode is launched for 70ms duration for the breakdown at low-loop voltage and around 150kW ECRH power for 50ms duration is launched in second EC pulse to heat the plasma. In case of Aditya-U, plasma heating is observed clearly as soft X-ray signal increases sharply with ECRH. In AdityaU tokamak, deuterium plasma experiments have been carried out and ECRH launched at the flat-top of deuterium plasma current. In deuterium plasma also ECR heating is observed as soft X-ray signal increases with ECH power. For SST-1, ECRH system is being upgraded with another 82.6GHz system, this system would be used to carry out plasma heating and start-up at second harmonic. The 82.6GHz system is already connected with the SST-1 tokamak, the old 82.6GHz-200kW Gyrotron will be upgraded to 400kW system to carry out effective heating experiments on SST-1 at higher ECRH power. The paper discusses the recent results of ECRH experiments carried out on tokamaks SST-1 & Aditya-U and presents the upgradation plan of EC system for SST-1.

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Section: Upgradation Plan Of Ecrh System On Sst-1mentioning

confidence: 75%

ECRH experiments on Tokamaks SST-1 & Aditya-U and ECRH upgradation plan for SST-1

Shukla

Patel²,

Patel³

et al. 2023

EPJ Web Conf.

Self Cite

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“…ECRH assistance should be the dominant scheme. Start-up with EC assistance has been applied on many machines, such as ISX-B [4], Alcator C-MOD [5], TCA [6], SINP [7], TRIAM-1 M [8], DIII-D [9][10][11][12], FTU [13], T-10 [14], HL-2A [15] and SST-1 [16]. Other RF methods can also play a role in the start-up [17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical modeling of plasma start-up assisted by electron drift injection on J-TEXT

et al. 2023

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Start-up is one of the critical phases for tokamak discharge. The electron drift injection (EDI) system has been developed on J-TEXT for start-up studies. The experiment of breakdown with EDI assisted has been conducted, which verified the effect of pre-ionization by EDI to achieve start-up at a lower Ohmic field voltage. A 0-dimensional model has been developed to explain the effect of EDI quantitatively. The comparison between the experiment and simulation verified the credibility of this model. Based on this model, the comparison between pure Ohmic heating start-up and EDI assisted start-up was presented, showing that EDI improved ionization, causing lower delay to the peak of hydrogen ionization and radiation losses and the electron and ion energy to rise more smoothly. This result verified the pre-ionization effect of the EDI to start-up quantitatively. The effects of injecting different currents and electron energy were investigated. The better pre-ionization effect can be realized by improving injected current, which can be a reference to the upgrading of EDI system.

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