ИСТИНА

Mercury, the planet closest to the Sun, has its own magnetic field, sufficient to create its own magnetosphere around the planet. It has been studied in detail during the MESSENGER (MERcury Surface, Space ENvironment, GEochemistry, and Ranging) mission. This spacecraft completed more than 4,000 revolutions around the planet from 2011 to 2015. We use the paraboloid model of Mercury’s magnetospheric magnetic field to determine the optimal parameters of Mercury’s magnetosphere current systems and internal planetary dipole parameters for all MESSENGER orbits. The formation of the magnetosphere is associated with the currents flowing in the space around the planet, which create their own magnetic field, super- imposed on the planetary internal magnetic field. These currents, and hence the magnetic field they create, can change from flyby to flyby, or even on the scale of one spacecraft orbit, due to the short reconfiguration time of the Mercury’s magnetosphere, which is on the order of several minutes [1]. To take into account these contributions and to refine the estimate of the planetary magnetic moment, a model of the magnetospheric field is required. In this work, we use a paraboloid model of the Mercury magnetosphere. It was introduced in [2] for the Mariner 10 data analysis, and then for the analysis of the first two MESSENGER flybys in [3], where the effect of dipole tilt was included. In [4], the paraboloid model was used to describe the erosion of Mercury’s magnetosphere. References: [1] Slavin J.A., Krimigis S.M., Acuña M.H. et al. MESSENGER: Exploring Mercury’s Magnetosphere // Space Sciences Reviews. 2007. V. 131. P. 133–160. https://doi. org/10.1007/s11214-007-9154-x. [2] Alexeev I.I., Belenkaya E.S., Bobrovnikov S.Yu. et al. Paraboloid model of Mercury’s magnetosphere // J. Geophysical Research. 2008. V. 113. Iss. A12. Art. No. A12210. https://doi.org/10.1029/2008JA013368. [3] Alexeev I.I., Belenkaya E.S., Slavin J.A. et al. Mercury’s magnetospheric magnetic field after the first two MESSENGER flybys // Icarus. 2010. V. 209. No. 1. P. 23–39. [4] Heyner D., Nabert C., Liebert E., Glassmeier K.-H. Concerning reconnection-induction balance at the magnetopause of Mercury // J. Geophysical Research. Space Physics.2016.V.121.Iss.4.P.2935–2961.https://doi.org/10.1002/2015JA021484. [5] Sitnik I.M., Alexeev I.I., Selugin O.V. The final version of the FUMILIM minimization package // Computer Physics Communications. 2020. V. 251. Art. No. 107202. DOI: 10.1016/j.cpc.2020.107202