The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The...The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.展开更多
The investigation of runaway electrons is expanded by different methods. The aim of this study is to show sawtooth oscillations of hard x-ray emission and with the help of sawtooth oscillations to obtain radial diffus...The investigation of runaway electrons is expanded by different methods. The aim of this study is to show sawtooth oscillations of hard x-ray emission and with the help of sawtooth oscillations to obtain radial diffusion coefficient and magnetic fluctuations. In the same way, the hard x-ray spectral evaluation is compared in several time intervals and it is shown that during discharge, the energy of the runaway electrons is less than 200？keV. Also, for typical plasmas, population of runaway electrons is measured at seven time intervals of 5ms and temporal evaluation of runaway electron mean energy. The sawtooth-like shape is observed in the hard x-ray range （10–1000？keV）. By the sawtooth oscillation method, the RE diffusion coefficient in radial transport in the IR-T1 plasma is Dr～0.5Dr～0.5m^2s^-1. The magnetic field fluctuation due to magnetic diffusion DmDm is given as br/Bt～10^-4.展开更多
文摘The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.
文摘The investigation of runaway electrons is expanded by different methods. The aim of this study is to show sawtooth oscillations of hard x-ray emission and with the help of sawtooth oscillations to obtain radial diffusion coefficient and magnetic fluctuations. In the same way, the hard x-ray spectral evaluation is compared in several time intervals and it is shown that during discharge, the energy of the runaway electrons is less than 200？keV. Also, for typical plasmas, population of runaway electrons is measured at seven time intervals of 5ms and temporal evaluation of runaway electron mean energy. The sawtooth-like shape is observed in the hard x-ray range （10–1000？keV）. By the sawtooth oscillation method, the RE diffusion coefficient in radial transport in the IR-T1 plasma is Dr～0.5Dr～0.5m^2s^-1. The magnetic field fluctuation due to magnetic diffusion DmDm is given as br/Bt～10^-4.
