Shulou(Shulou.com)11/24 Report--

CTOnews.com, January 16, according to the website of Shanghai Astronomical Observatory of the Chinese Academy of Sciences, during the 2021 Martian Sunshine period (late September to mid-October), with the support of the National Space Administration Chinese and foreign scientific research institutions, such as the Shanghai Observatory of the Chinese Academy of Sciences, the National Center for Space Sciences of the Chinese Academy of Sciences, the School of Earth and Space Sciences of Peking University, the National Astronomical Observatory of the Chinese Academy of Sciences, the University of Tasmania in Australia and the European Institute of very long baseline Interferometry, have jointly carried out sun occultation observations of the sun using the measurement and control communication signals of the "Tianmen-1" orbiter and the "Mars Express" orbiter. Important research results have been achieved. Related research papers have been published in the international professional journal "Astrophysics KuaiBao (The Astrophysical Journal Letters)".

Mars Sunling refers to the natural phenomenon that the earth and Mars move to both sides of the sun and the three are almost in a straight line. During the Martian sunrise, the radio signals sent by the probe to the earth measurement and control station pass through the nearby solar space (hereinafter referred to as the "solar space"), and the signal intensity and frequency change due to the interference of solar electromagnetic radiation. through the study of these effects, scientists can invert and study the activity of the sun.

The position relationship between Earth, Mars and the Sun during ▲ Riling. The picture is from the website of Shanghai Astronomical Observatory of the Chinese Academy of Sciences. The following is the same as during the 2021 Mars Sunshine. The Tian Meng-1 orbiter and the ESA Mars Express orbiter mission team control two probes to regularly send radio signals to Earth. Scientists from many countries use more than a dozen radio telescopes at home and abroad. The signals of the two detectors affected by the sun are observed.

On October 9, 2021, when the projection point of Mars (the projection of Mars near the sun) was 2.6 Rs (the radius of the sun) from the center of the sun, researchers found that six stations received a disturbance of the strongest ±20Hz frequency of radio signals from "Tian Meng I" and "Mars Express" for up to 10 minutes.

Through the analysis of the disturbance signal, the researchers found that when the radio signal propagated through the solar space, the total electron content in this area changed by thousands of TECU (total electronic units, 1TECU=1016 electrons per square meter). Compared with the optical remote sensing data obtained by large Angle Spectrocoronometer (LASCO) in the same period, it is found that the change of total electron content is caused by coronal mass ejection (CME). As one of the most violent burst phenomena in the sun, CME phenomenon can quickly project a large number of plasmas carrying magnetic field. The refraction and scattering effects of these plasmas on the signal will lead to signal frequency disturbance.

Because the time for the same frequency disturbance signal to arrive at different stations is different, the plasma ejection velocity of CME can be calculated from the propagation distance and time between the frequency disturbance signal and each station, so the joint measurement of multi-stations can be used to study the spatial propagation of solar activity in solar space.

At the same time, the coronal current waves caused by the interaction between CME and coronal current are observed in a smaller spatial scale near the Martian projection point. Coronal current wave is a large-scale coronal wave phenomenon, also known as "ribbon floating over the sun", which reflects the restriction of magnetic field on the motion of solar wind plasma.

CTOnews.com learned that the primary high-speed solar wind was detected when CME left. The primary solar wind refers to the solar wind that has just emitted from the sun.

According to reports, this work benefits from the high sensitivity of the radio remote sensing observation method of the detector, as well as the advantages of high time resolution and high spatial resolution of multi-station joint observation. This method can observe the small-scale and rapid changes in space which can not be accessed by in-situ detectors and can not be recognized by optical means, which is helpful for researchers to study the solar space environment and its impact on deep space communication in more detail.

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