This paper describes the experimental analysis and preliminary investigation of the predictability of pitch angle scattering(PAS) events through the electron cyclotron emission(ECE)radiometer signals at the ADITYA-Upg...This paper describes the experimental analysis and preliminary investigation of the predictability of pitch angle scattering(PAS) events through the electron cyclotron emission(ECE)radiometer signals at the ADITYA-Upgrade(ADITYA-U) tokamak. For low-density discharges at ADITYA-U, a sudden abnormal rise is observed in the ECE signature while other plasma parameters are unchanged. Investigations are done to understand this abrupt rise that is expected to occur due to PAS. The rise time is as fast as 100 μs with a single step and/or multiple step rise in ECE radiometer measurements. This event is known to limit the on-axis energy of runaway electrons. Being a repetitive event, the conditions of its repetitive occurrence can be investigated, thereby exploring the possibility of it being triggered and surveyed as an alternate runaway electron mitigation plan. Functional parameterization of such events with other discharge parameters is obtained and the possibility to trigger these events is discussed.PREDICT code is used to investigate the possible interpretations for the PAS occurrence through modeling and supporting the ECE observations. The trigger values so obtained experimentally are set as input criteria for PAS occurrence. Preliminary modeling investigations provide reliable consistency with the findings.展开更多
The Ohmically heated circular limiter tokamak ADITYA （R0 = 75 cm, a = 25 cm） has been upgraded to a tokamak named the ADITYA Upgrade （ADITYA-U） with an open divertor configuration with divertor plates. The main go...The Ohmically heated circular limiter tokamak ADITYA （R0 = 75 cm, a = 25 cm） has been upgraded to a tokamak named the ADITYA Upgrade （ADITYA-U） with an open divertor configuration with divertor plates. The main goal of ADITYA-U is to carry out dedicated experiments relevant for bigger fusion machines including ITER, such as the generation and control of runaway electrons, disruption prediction, and mitigation studies, along with an improvement in confinement with shaped plasma. The ADITYA tokamak was dismantled and the assembly of ADITYA-U was completed in March 2016. Integration of subsystems like data acquisition and remote operation along with plasma production and preliminary plasma characterization of ADITYA-U plasmas are presented in this paper.展开更多
文摘This paper describes the experimental analysis and preliminary investigation of the predictability of pitch angle scattering(PAS) events through the electron cyclotron emission(ECE)radiometer signals at the ADITYA-Upgrade(ADITYA-U) tokamak. For low-density discharges at ADITYA-U, a sudden abnormal rise is observed in the ECE signature while other plasma parameters are unchanged. Investigations are done to understand this abrupt rise that is expected to occur due to PAS. The rise time is as fast as 100 μs with a single step and/or multiple step rise in ECE radiometer measurements. This event is known to limit the on-axis energy of runaway electrons. Being a repetitive event, the conditions of its repetitive occurrence can be investigated, thereby exploring the possibility of it being triggered and surveyed as an alternate runaway electron mitigation plan. Functional parameterization of such events with other discharge parameters is obtained and the possibility to trigger these events is discussed.PREDICT code is used to investigate the possible interpretations for the PAS occurrence through modeling and supporting the ECE observations. The trigger values so obtained experimentally are set as input criteria for PAS occurrence. Preliminary modeling investigations provide reliable consistency with the findings.
文摘The Ohmically heated circular limiter tokamak ADITYA （R0 = 75 cm, a = 25 cm） has been upgraded to a tokamak named the ADITYA Upgrade （ADITYA-U） with an open divertor configuration with divertor plates. The main goal of ADITYA-U is to carry out dedicated experiments relevant for bigger fusion machines including ITER, such as the generation and control of runaway electrons, disruption prediction, and mitigation studies, along with an improvement in confinement with shaped plasma. The ADITYA tokamak was dismantled and the assembly of ADITYA-U was completed in March 2016. Integration of subsystems like data acquisition and remote operation along with plasma production and preliminary plasma characterization of ADITYA-U plasmas are presented in this paper.
