AI 中文总结
该研究增强了Gauribidanur射电日像仪，使其可同时观测太阳日冕的斯托克斯I、V射电辐射，初步结果显示其能探测宁静与活动太阳的相关斯托克斯V辐射，为日冕磁场测量提供支撑。
AI 中文摘要
太阳光球层的磁场强度（B）通常通过塞曼效应测量，但色球层和日冕中无法进行此类测量。位于印度班加罗尔附近的Gauribidanur射电日像仪（GRAPH）已成功开展太阳日冕在低频率（≤100 MHz）下的总强度（斯托克斯I）观测数年，该频率范围的太阳射电辐射通常起源于日心距r≥1.2 R⊙处。我们近期对GRAPH进行了增强，目标是观测太阳日冕，尤其是“宁静”日冕的圆偏振射电辐射（斯托克斯V）。结合低频斯托克斯I、V射电图像与建模技术，可定期计算太阳日冕的磁场强度。本文详细介绍了为增强GRAPH以同时观测太阳日冕的斯托克斯I、V射电辐射所采取的流程及校准方法。初步结果显示，增强后的GRAPH除了能探测“活动”太阳非热射电爆发相关的斯托克斯V辐射外，还可有效探测“宁静”太阳热辐射相关的斯托克斯V辐射，频率≤100 MHz。
英文摘要
The magnetic field strengths (B) in the solar photosphere are routinely measured using the Zeeman effect. However, such measurements are not available in the solar chromosphere and corona. The Gauribidanur RAdioheliograPH (GRAPH), near Bangalore in India, has been successfully carrying out total intensity (Stokes I) observations of the solar corona at low frequencies ($\lesssim$ 100 MHz) for several years now. Radio emission from the Sun in the above frequency range originates typically in the heliocentric distance r $\gtrsim$ 1.2 $R_\odot$ . We recently augmented GRAPH with the aim to observe circularly polarized radio emission (Stokes V) from solar corona, in particular, from the 'quiet' corona. Combining the low frequency Stokes I & V radio images, and modeling techniques, it is possible to calculate the magnetic field strengths in the solar corona on regular basis. This work details the procedures undertaken to augment the GRAPH for simultaneous observations of both Stokes I & V radio emission from the solar corona, and the calibration procedure. Preliminary results indicate that the augmented GRAPH can effectively detect Stokes V emission associated with thermal emission from the 'quiet' Sun at frequencies $\lesssim$ 100 MHz, in addition to Stokes V emission associated with the non-thermal radio bursts from the 'active' Sun.
CommentsThere are 25 pages with 18 figures in a manuscript. This is currently submitted to 'Solar Physics' journal
