Physical Effects of the Yushu Meteoroid: 2

A comprehensive modeling of the processes in all geospheres caused by the fall and explosion of the Yushu meteoroid in the Qinghai Province (People’s Republic of China) on December 22, 2020, was performed. Thermodynamic and plasma effects, as well as the effects of the plume and turbulence, accompanying the passage of the Yushu meteoroid were estimated. It is shown that the passage of the celestial body led to the formation of a gas and dust plume. The heated meteoroid wake cooled down for several hours. Four stages of cooling of the meteoroid wake are considered. The first of them lasted approximately 0.2 s, and the temperature of the wake decreased by half due to radiation. During the second stage (~3 s), cooling continued due to radiation and expansion of the wake, and the temperature decreased by 20%. During the third stage, which lasted 6 s, the explosion products and heated gas (thermal column) with an acceleration of approximately 30 m/s² rose at a speed of 140 m/s, and the temperature decreased by 10%. The fourth stage lasted approximately 50 s, the thermal column intensively absorbed cold air, gradually cooled, and slowed down. The maximum height of the thermal column reached 7–8 km. The explosion products (dust particles and aerosols) that were part of the thermal column were subsequently involved in three processes: slow settling to the Earth’s surface, turbulent mixing with the surrounding air, and transportation by prevailing winds around the planet. It is shown that the effect of turbulence in the meteoroid’s wake was well expressed, while magnetic turbulence had hardly any effect. The main parameters of the plasma in the wake are estimated: height dependences of the linear and volume electron densities, values of their relaxation times, particle collision frequencies, plasma specific conductivity, and relaxation times of the electron temperature. It is shown that the linear and volume electron densities in the wake at the initial moment were 10¹⁹–4 × 10²² m^–1 and 10¹⁷–10²¹ m^–3 and the plasma specific conductivity was of the order of 10³ Ω^–1m^–1. The role of the dust component of the plasma is discussed.