42-GHz/500-kW Electron Cyclotron Resonance Heating System on Tokamak SST-1

Shukla, B. K.; Patel, Paresh; Patel, Jatin; Babu, Rajan; Patel, Harshida; Dhorajia, Pragnesh; Singh, Prashant Kumar; Sumod, C. B.; Thakkar, D. P.; Gupta, L. N.; Barua, Ujjwal K.; Jha, Ratneshwar; Bora, D.; Shmelev, M.Yu.; Irkhin, Vladimir; Khozin, M. A.; Belousov, V. I.; Soluyanova, E. A.; Tai, E. M.; Gasainiev, Zakhar; Денисов, Г. Г.

doi:10.1109/tps.2014.2369517

Cited by 9 publications

(3 citation statements)

References 15 publications

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“…Considering Debye shielding with the electron temperature effect, Hooper [22] calculated a microfield distribution in plasma for different a with the parameter a = (r i /ρ D ). Now, r i is the ion-ion minimum distance, which can be calculated from 4 3 πn i r 3 i = 1 ⇒ r i = ( 3 4πn i ) 1/3 , and ρ D is the Debye radius, which is ρ D = ( ϵ0kBTe nee 2 ) 1/2 . In the present case, calculations show that a = 0.06 for T e = 3 eV and n i ≈ 10 18 m −3 .…”

Section: Resultsmentioning

confidence: 99%

“…Presently, the SST-1 current start-up is routinely carried out by an ECRH system operated by a Gyrotron with a power rating of 500 kW for the duration of 500 ms [4] at 42GHz microwave frequency. It can launch ECR waves in the second harmonics at 0.75 T and at a fundamental frequency at 1.5 T. The toroidal magnetic field of SST-1 can be varied between 0 and 3 T [5].…”

Section: Introductionmentioning

confidence: 99%

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Development of a novel spiral antenna system for low loop voltage current start-up at the Steady State Superconducting Tokamak (SST-1)

Basu

Raju

Singh

et al. 2021

Plasma Phys. Control. Fusion

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In general, superconducting tokamaks require low loop voltage current start-up for the safety purpose of their poloidal field coils. The loop voltage inside the vacuum vessel of Steady State Superconducting Tokamak (SST-1) is low in nature since its central solenoid is located outside the cryostat. The low loop voltage current start-up of the SST-1 is routinely performed by using the electron cyclotron resonance (ECR) method at the toroidal magnetic field B t = 1.5 T (first harmonic) and 0.75 T (second harmonic). Recently, an alternative RF-based plasma current start-up system has been planned for operating the machine, especially for a higher toroidal magnetic field regime 1.5 T ⩽ B t ⩽ 3 T . The system was already developed based on an antenna system, made of a series of combinations of two flat spiral antennas, to assist plasma current start-up at a lower inductive electric field. It has already been tested and installed in the SST-1 chamber. The system testing was performed without a background magnetic field within the frequency regime of 35 MHz–60 MHz at present. The test results show that it can produce an electron density of n e ≃ 10 16 m − 3 measured by the Langmuir probe at the expense of 500 W RF power. The spectroscopy results indicate its capability of producing plasma density greater than 10 13 m − 3 and an electron temperature of T e = 2 –6 eV. In addition, the results also show the presence of a turbulent electric field of the order of 106 V m−1 at the antenna center and a finite anomalous temperature of neutral particles. Calculations show that the obtained density is sufficient for SST-1 low loop voltage plasma breakdown. The antenna system is also capable of producing plasma at higher frequencies. This article will discuss the development of the prototype and the installed antenna system along with their test results in detail.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a novel spiral antenna system for low loop voltage current start-up at the Steady State Superconducting Tokamak (SST-1)

Basu

Raju

Singh

et al. 2021

Plasma Phys. Control. Fusion

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“…This system has two microwave sources, one 42 GHz gyrotron capable of providing 500 kW power for 500 ms and one 82 GHz gyrotrons capable of delivering 200 kW power for 1000s. This power is transmitted to tokamak through corrugated waveguide based transmission system which consists of matching optical unit (MOU), DC breaks, meter bends with bidirectional coupler, polarizer and vacuum window [2][3].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of Steerable ECRH Launcher for SST-1 Tokamak

Mistry

Shukla

2017

EPJ Web Conf.

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In the tokamaks ECRH system is used for pre-ionization, start up, heating, current drive and suppression of NTMs (Neo Classical Tearing Modes). A Standard ECRH system consists of high power microwave source Gyrotron, circular corrugated waveguide based transmission line and launcher. The Focused ECH power is launched into plasma through launcher. The microwave beam emerges out from circular corrugated waveguide and propagates freely in air with finite divergence. So focusing and plane mirror combination is used to launch focused beam in plasma. Thus an ECRH launcher consists of metallic profiled and plane mirror, UHV compatible vacuum barrier window and a UHV gate valve. One 42 GHz gyrotron capable of delivering 500 kW of power for 500 ms and other 82 GHz gyrotron capable of delivering 200 kW of power for 1000s are used for SST-1 ECRH system. The launcher design consists of mirror design, design of supports and design of steering mechanism to provide suitable movements with minimum backless error. The whole assembly is UHV compatible. The launcher is capable of steering the beams by ±20° in both toroidal and poloidal directions. Mirrors are given motion by means of one rotary and one linear feedthrough. For 82 GHz launcher active cooling is provided, whereas for 42 GHz launcher no active cooling is provided. A detailed analysis is carried out for the mirrors of the high power launcher. The heat load for the 82 GHz launcher is 2 kW (~1% absorption) and for 42 GHz launcher it is 5 kW. For 82 GHz launcher, the maximum steady state surface temperatures of focusing and reflecting mirrors are 315K and 323K and von-mises stresses are within 10 MPa. Similarly for 42 GHz launcher maximum temperatures observed during 500 ms pulse are 301K and 303K for focusing and reflecting mirrors respectively. This paper explains the mechanical and thermal design and analysis of the launcher for the ECRH system.

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