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Absolute calibration of solar radio flux density at 9375 MHz
112
Abstracts
Interaction of coronal loops AAnS 3213 (1991) 233-238 ZHANG Zhen-da (Department of Astronomy, Nanjing University) R. N. Smartt (National Solar Observatory, U.S.A.) In this paper the occasional transient enhancements at the interaction regions of some loops as recorded in coronal images of FeXN and FeX (6374A), and the associated images in Ha have been analyzed. The brightness of a green line enhancement gradually increases to a maximum and then fades with a typical lifetime of about 20-30 minutes. The maximum of the red line enhancement at the same location follows that of the green line on average by 8.6 minutes, and Ha then reaches a maximum in extent on average 9.3 minutes after the red line maximum. This phenomenon is interpreted as a process of localized magnetic reconnection. Estimates of the electron density from the cooling time, and the values of dissipated energy are obtained by two separate methods. Key words: Coronal loops-interaction-electron density and energy
Absolute calibration of solar radio flux density at 9375 MHz AAnS 3213 (1991) 239-246 ZHOU Shu-rong XU Fu-ying YU Xing-feng (Purple Mountain Observatory, Chinese Academy of Sciences) We have developed a large pyramidal horn and two black-body boxes to measure solar radio fluxes and to correct the gain of a paraboloid antenna at 9375 MHz. During the absolute calibration, we obtained solar radio fluxes with an optimal pyramidal horn at 9375 MHz. They roughly agree with the values of TYKW at 9400 MHz. The difference between the systems is kO.S%. The measuring accurcy of the fluxes is f3.5% (the accidental error is f1.3% and the systematic error is f2.2%). The gain of the paraboloid antenna is 40.50 f0.02db. The factor that converts antenna temperature into radio flux is 0.3139. By comparing the computed solar radio fluxes based on the converting factor with that of TYKW at 9400 MHz, we obtamed Ss_&Sssr5 = 1.01. The correlation coefficient is 0.95. The results indicate that using an optimal pyramidal horn to observe the sun and two black bodies with different temperatures as the temperature standards at the aperture plane of the horn is one of the best and reliable method for absolute calibration of both solar radio emissive fluxes and the antenna gain. Key words: Sun-radio flux-absolute measurement
Abstracts
Interaction of coronal loops AAnS 3213 (1991) 233-238 ZHANG Zhen-da (Department of Astronomy, Nanjing University) R. N. Smartt (National Solar Observatory, U.S.A.) In this paper the occasional transient enhancements at the interaction regions of some loops as recorded in coronal images of FeXN and FeX (6374A), and the associated images in Ha have been analyzed. The brightness of a green line enhancement gradually increases to a maximum and then fades with a typical lifetime of about 20-30 minutes. The maximum of the red line enhancement at the same location follows that of the green line on average by 8.6 minutes, and Ha then reaches a maximum in extent on average 9.3 minutes after the red line maximum. This phenomenon is interpreted as a process of localized magnetic reconnection. Estimates of the electron density from the cooling time, and the values of dissipated energy are obtained by two separate methods. Key words: Coronal loops-interaction-electron density and energy
Absolute calibration of solar radio flux density at 9375 MHz AAnS 3213 (1991) 239-246 ZHOU Shu-rong XU Fu-ying YU Xing-feng (Purple Mountain Observatory, Chinese Academy of Sciences) We have developed a large pyramidal horn and two black-body boxes to measure solar radio fluxes and to correct the gain of a paraboloid antenna at 9375 MHz. During the absolute calibration, we obtained solar radio fluxes with an optimal pyramidal horn at 9375 MHz. They roughly agree with the values of TYKW at 9400 MHz. The difference between the systems is kO.S%. The measuring accurcy of the fluxes is f3.5% (the accidental error is f1.3% and the systematic error is f2.2%). The gain of the paraboloid antenna is 40.50 f0.02db. The factor that converts antenna temperature into radio flux is 0.3139. By comparing the computed solar radio fluxes based on the converting factor with that of TYKW at 9400 MHz, we obtamed Ss_&Sssr5 = 1.01. The correlation coefficient is 0.95. The results indicate that using an optimal pyramidal horn to observe the sun and two black bodies with different temperatures as the temperature standards at the aperture plane of the horn is one of the best and reliable method for absolute calibration of both solar radio emissive fluxes and the antenna gain. Key words: Sun-radio flux-absolute measurement