The resonant magnetic perturbation （RMP） coils have been successfully designed and installed on the Experimental Advanced Superconducting Tokamak （EAST）. Using the reflectometer systems, the density profile and th...The resonant magnetic perturbation （RMP） coils have been successfully designed and installed on the Experimental Advanced Superconducting Tokamak （EAST）. Using the reflectometer systems, the density profile and the density fluctuations during magnetic perturbations （MPs） phase have been investigated. During the experiments, two different cases are studied separately： steady MPs and rotating MPs. In both cases, a strongly density pump-out has been observed. In the steady MPs cases, an enhancement of the low frequency （〈60 kHz） density fluctuations in H-mode phase has been observed. The plasma density boundary out-shifts 5~ caused by the MPs. The pedestal density gradient is reduced by 50%, while the radial location nearly stays unchanged. In the rotating MPs, the line-averaged density, the D~ emission at the divertor region and the spectrum of the density fluctuations are modulated. The results suggest that the low frequency （〈60 kHz） density fluctuations may contribute to the strong density pump-out.展开更多
The mono-frequency peak luminosity and the corresponding photon energy of the time-integrated （L~, Eg） and peak time （L~, ffp） vfv spectra were derived for a sample of 38 redshift-known Fermi GRBs by fitting the s...The mono-frequency peak luminosity and the corresponding photon energy of the time-integrated （L~, Eg） and peak time （L~, ffp） vfv spectra were derived for a sample of 38 redshift-known Fermi GRBs by fitting the spectra with the Band function. It was found that Ept is generally consistent with Ep, and Lp is averagely three times larger than Lp. The slope of the Lp1 -Etp relation was consistent with that of the Lps - Eps relation. The photon indices in the peak time spectrum, particularly, the index of the low energy end was, were statistically larger than that in the time-integrated spectrum. These results indicate that Lp and Ep are dominated by Lp1 and Ept, respectively. The difference of the spectral indices between the time-integrated and peak time spectra may be because of the overlap effect of a series of time-resolved spectra within a GRB. Our simulations, which were based on the observed spectral evolution and correlation between the energy flux and the peak energy within individual GRBs support our speculations. The Lt - Et, relation may be less contaminated by the overla!a effect, and it would may be an intrinsic feature of radiation ohvsics.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2014GB106000,2014GB106003 and2015GB110001)National Natural Science Foundation of China(Nos.11275234,11305215,11305208,11405214 and 11505221)
文摘The resonant magnetic perturbation （RMP） coils have been successfully designed and installed on the Experimental Advanced Superconducting Tokamak （EAST）. Using the reflectometer systems, the density profile and the density fluctuations during magnetic perturbations （MPs） phase have been investigated. During the experiments, two different cases are studied separately： steady MPs and rotating MPs. In both cases, a strongly density pump-out has been observed. In the steady MPs cases, an enhancement of the low frequency （〈60 kHz） density fluctuations in H-mode phase has been observed. The plasma density boundary out-shifts 5~ caused by the MPs. The pedestal density gradient is reduced by 50%, while the radial location nearly stays unchanged. In the rotating MPs, the line-averaged density, the D~ emission at the divertor region and the spectrum of the density fluctuations are modulated. The results suggest that the low frequency （〈60 kHz） density fluctuations may contribute to the strong density pump-out.
基金supported by the National Basic Research Program of China(Grant No.2014CB845800)the National Natural Science Foundation of China(Grant No.11025313)+1 种基金Guangxi Science Foundation(Grant No.2013GXNSFFA019001)Key Laboratory for the Structure and Evolution of Celestial Objects of Chinese Academy of Sciences,and the Strategic Priority Research Program"The Emergence of Cosmological Structures"of the Chinese Academy of Sciences(Grant No.XDB09000000)
文摘The mono-frequency peak luminosity and the corresponding photon energy of the time-integrated （L~, Eg） and peak time （L~, ffp） vfv spectra were derived for a sample of 38 redshift-known Fermi GRBs by fitting the spectra with the Band function. It was found that Ept is generally consistent with Ep, and Lp is averagely three times larger than Lp. The slope of the Lp1 -Etp relation was consistent with that of the Lps - Eps relation. The photon indices in the peak time spectrum, particularly, the index of the low energy end was, were statistically larger than that in the time-integrated spectrum. These results indicate that Lp and Ep are dominated by Lp1 and Ept, respectively. The difference of the spectral indices between the time-integrated and peak time spectra may be because of the overlap effect of a series of time-resolved spectra within a GRB. Our simulations, which were based on the observed spectral evolution and correlation between the energy flux and the peak energy within individual GRBs support our speculations. The Lt - Et, relation may be less contaminated by the overla!a effect, and it would may be an intrinsic feature of radiation ohvsics.
