Реферат: KEYWORDS: Mars, ExoMars TGO, radiation measurements, galactic cosmic rays (GCR), solar energetic particle (SEP) event, comparison ABSTRACT: The dosimetric telescope Liulin-MO for measuring the ionizing radiation environment onboard the ExoMars Trace Gas Orbiter (TGO) is a module of the Fine Resolution Epithermal Neutron Detector (FREND) [1, 2]. Presented are the main results from Liulin-MO measurements in TGO Mars science orbit (400 km altitude, 74° inclination) of the radiation doses and particle fluxes of GCR and of SEP events occurred in the first half of 2024. The results show that the dose rate and particle flux of GCR in April 2024 during the increasing phase of the 25th solar cycle are about 40 % of the corresponding values measured during the 24th solar cycle minimum in March – August 2020. During the increasing phase of the 25th solar cycle a number of SEP events were observed in TGO Mars orbit [3–5]. In this paper we discuss the SEP events registered by Liulin-MO from January to June 2024. The SEP event that started on 20 May 2024 is the most powerful measured up to the moment on TGO. During this event the SEPs dose is 24.7 mGy in silicon-equal to the dose for about 200 days from GCR in undisturbed conditions. Measurements by Liulin-MO during SEP events are compared to measurements by other satellites and instruments around the Earth and in the heliosphere. The results of the radiation measurements on TGO are of importance for assessment of the radiation risk and planning of the future manned and robotic missions to Mars. The Liulin-MO observations during SEP events in Mars orbit may contribute to the investigation of the distribution of the solar cosmic rays in the heliosphere. REFERENCES: [1] Mitrofanov I., Malakhov A., Bakhtin B. et al. Fine Resolution Epithermal Neutron Detector (FREND) onboard the ExoMars Trace Gas Orbiter // Space Science Reviews. 2018. V. 214. Iss. 5. Article 86. https://doi.org/10.1007/s11214-018-0522-5. [2] Semkova J., Koleva R., Benghin V. et al. Charged particles radiation measurements with Liulin-MO dosimeter of FREND instrument aboard ExoMars Trace Gas Orbiter during the transit and in high elliptic Mars orbit // Icarus. 2018. V. 303. P. 53–66. https://doi.org/10.1016/j.icarus.2017.12.034. [3] Semkova J., Koleva R., Benghin V. et al. Observation of the radiation environment and solar energetic particle events in Mars orbit in May 2018 – June 2022 // Life Sciences in Space Research. 2023. V. 39. P. 106–118. https://doi.org/10.1016/j.lssr.2023.03.006. [4] Guo J., Li X., Zhang J., Dobynde M. I. et al. The first ground level enhancement seen on three planetary surfaces: Earth, Moon, and Mars // Geophysical Research Letters. 2023. V. 50. Article e2023GL103069. https://doi.org/10.1029/2023GL103069. [5] Semkova J., Benghin V,. Koleva R. et al. New Results of Radiation Study on Board TGO ExoMars in 2018–2023 // Solar System Research. 2024. V. 58. No. 4, P. 367–376.

Библиографическая ссылка: Semkova J. , Benghin V. , Koleva R. , Krastev K. , Matviichuk Y. , Tomov B. , Bankov N. , Maltchev S. , Dachev T. , Mitrofanov I. , Golovin D. , Mokrousov M. , Litvak M. , Kozyrev A. , Shurshakov V. , Drobyshev S.
RADIATION ENVIRONMENT ON TGO MARS ORBIT DURING SOLAR PARTICLE EVENTS IN 2024
15ый международный симпозиум по исследованиям Солнечной системы Oct 21, 2024 - Oct 25, 2025