Type Ⅱ Radio Burst was Detected for the First Time by Qitai LFRA at 18-50 MHz

Type Ⅱ radio bursts are the best tracers of Coronal Mass Ejections (CME). The coronal or interplanetary shocks are generated along with a dramatic effect on the Earth's magnetosphere, when CME exceed the local Alfin velocity. The detection of type Ⅱ radio bursts in the radio band manifests the generation of coronal shock waves. The prediction of the arrival time of shock waves to the Earth is essential to the space weather prediction. Type Ⅱ radio burst was detected for the first time by Qitai low frequency (Qitai LFRA) at around 06: 20 UT on September 28, 2021, with a frequency coverage of 18-50 MHz and a duration of more than 10 minutes. Since virtually no observation with effective spatial resolution have been made at extremely low frequency (<40 MHz) band, there is a great possibility to discover unknown phenomena at this band in future. Our observation shows that Qitai LFRA has good performance (Typical gain: 6 dBi) and high sensitivity (-78 dBm/125 kHz, DR: 72 dB), and can play a unique role in the 25^th annual solar activity peak.