The observation of the South Atlantic Anomaly with the particle monitors onboard Insight-HXMT

The South Atlantic Anomaly (SAA) is a region of weakened geomagnetic field and in the previous studies, it shows a secular variation with time which is associated with the changing of the magnetic moment. This region also consists of large amounts of energetic charged particles and is danger to space vehicle and astronauts. Thus, it is essential to know the location and movement of the SAA. In this study, three particle monitors onboard Insight-HXMT are used to track the movement and location of the SAA from 2017 June 19 to 2019 June 19. Several particle flux maps are built to show the location of the SAA peak with time. In a grid of map, the particle count is determined by the maximum count rate and the averaged count rate, respectively. We find the results of both methods are consistent very well with each other in deriving the drift rate. The result shows the SAA peak moves westwards with an average drift rate of 0.43 +/- 0.01 degrees/yr in longitude and moves northwards with an average drift rate of 0.17 +/- 0.01 degrees/yr in latitude, and the drift rate is slightly larger than the result from IGRF 12 (0.3 degrees/yr) in longitude, but in latitude, the result of IGRF 12 have no obvious change with time. (C) 2020 Elsevier B.V. All rights reserved.