[PEM17-P17] Summary of the five-year extended observations of Nobeyama Radioheliograph
Keywords:solar radio, solar flare, solar activity
Nobeyama Radioheliograph (NoRH) had been operated by the International Consortium for the Continued Operation of Nobeyama Radioheliograph (ICCON) since April 2015. However, the operation of NoRH finished at the end of March in 2020. Nagoya University collected the operational costs from international/domestic partners was unique and operated NoRH as a representative of ICCON. This style was very unique in the Japanese solar telescopes. The daily check of the instruments/computers/data were done by international/domestic collaborators. Finally, for five years, 33 researchers in nine countries (Belgium, China, Germany, Japan, South Korea, Russia, Switzerland, U.K., U.S.A.) did this task as a chief observer. Thanks to their contributions, scientific data were taken for almost the whole period except the following two periods, from late January 2018 to early April 2018, and from early May 2019 to early June 2019.
The original scientific targets were ‘particle acceleration in solar flares’ and ‘long-term solar activity variation’ for this extension. Unfortunately, since the solar flare activity was very low since April 2015, only 38 solar flares (max ~ M6.7 class) were detected during this extension period. Before the extension, about 900 flares were observed. So the increment of solar flare data was not so large. As for the latter topic, we could derive the data of the polar brightening in this solar cycle in addition to the previous two cycles. Then, Gopalswamy et al. (2018) predicted the peak sunspot number of the next solar cycle from the polar brightness at 17 GHz and Fujiki et al. (2019) found the very good correlation between the solar wind speed and the polar brightness at 17 GHz.
One of the most outstanding outcomes is the growth of the international collaboration in this field. Based on this activity, now we are considering the next framework of the international collaboration with the Chinese new solar radio telescope, so-called MUSER.
The original scientific targets were ‘particle acceleration in solar flares’ and ‘long-term solar activity variation’ for this extension. Unfortunately, since the solar flare activity was very low since April 2015, only 38 solar flares (max ~ M6.7 class) were detected during this extension period. Before the extension, about 900 flares were observed. So the increment of solar flare data was not so large. As for the latter topic, we could derive the data of the polar brightening in this solar cycle in addition to the previous two cycles. Then, Gopalswamy et al. (2018) predicted the peak sunspot number of the next solar cycle from the polar brightness at 17 GHz and Fujiki et al. (2019) found the very good correlation between the solar wind speed and the polar brightness at 17 GHz.
One of the most outstanding outcomes is the growth of the international collaboration in this field. Based on this activity, now we are considering the next framework of the international collaboration with the Chinese new solar radio telescope, so-called MUSER.