On the thermal atmospheric escape of π Men c

In this work we present the results of the modeling of exoplanet pi Men c upper atmosphere, produced using the previously developed one-dimensional self-consistent aeronomic model. The model used takes into account the contribution of suprathermal particles, which significantly refines the heating function of the atmosphere. The hight profiles of temperature, velocity and density were obtained, the atmospheric mass-loss rate was calculated. The presence of two hight-scales in the structure of the atmosphere was found: the first corresponds to a relatively dense stationary atmosphere, the second to a more rarefied corona.

On the thermal atmosphere evaporation of hot neptune GJ 436b

В данной работе с помощью одномерной самосогласованной аэрономической модели были получены высотные профили температуры, скорости и плотности для горячего нептуна GJ 436b. Мы проследили расширение газовой оболочки под действием нагрева от жесткого излучения родительской звезды от тонкого атмосферного слоя 1.02R 0 до 5R 0 . Используемая модель учитывает вклад надтепловых частиц, что значительно уточняет функцию нагрева атмосферы. Установлено, что формируется структура атмосферы с двумя характерными шкалами высоты, отвечающими относительно плотной атмосфере и более разреженной короне. Также был посчитан темп оттока атмосферы, составивший около 1.6 × 10 9 г с -1 , что ниже результатов, полученных авторами других расчетов. In this work the height profiles of temperature, velocity, and density were obtained for the hot neptune GJ 436b, using a one-dimensional self-consistent aeronomic model. We traced the expansion of the gas envelope affected by heating from the extreme radiation of the host star from the thin atmospheric layer 1.02R 0 up to 5R 0 . The model used takes into account the contribution of suprathermal particles, which significantly refines the atmospheric heating function. It was found that the structure of the atmosphere is being formed with two characteristic altitude scales corresponding to a relatively dense atmosphere and a more rarefied corona. The atmospheric mass loss rate was also calculated, it was found to be about 1.6 × 10 9 g s -1 , which is lower than the results obtained by the authors of other calculations.

The Suprathermal Particles and Charge Fluctuation Effects on Waves in Complex Plasma

In the frame of kinetic theory we investigated the effects of suprathermal particles and dust charge fluctuations due to the inelastic collision between the dust grains and plasma particles by calculating the longitudinal dielectric permittivity in an unmagnetized dusty plasma on the wave modes propagating in a complex plasma. The ion and electron distribution were assumed to be Maxwell and Kapa distribution in the systems. It was shown that the wave frequency can be analyzed for various values of the spectral index K and the dust charge fluctuations. The landau damping rate and Propagation rate in dust charge fluctuation presence increase

Particle Acceleration in Earth’s Global Magnetosphere: a Multiple Step Process

<p>Particle velocity distribution functions measured by spacecraft show that suprathermal ion and electron populations are a common feature of Earth’s magnetosphere.  An outstanding question has been to determine the acceleration processes that lead to the formation of these suprathermal particle populations. Very often, it has been challenging to explain the high levels of energy reached by these particles by simply invoking local processes such as magnetic reconnection. In this presentation, we investigate the hypothesis that suprathermal particle populations increase if the acceleration occurs over multiple steps through different acceleration mechanisms at different spatial locations in Earth’s magnetosphere.  For example, particles transported to the magnetotail which have been accelerated first in the dayside reconnection region could be further accelerated in the tail reconnection regions and then gain additional energy through Fermi and/or betatron acceleration as they convected back to the dayside magnetopause. Since local kinetic processes dominate the acceleration of ions and electrons in the magnetosphere, it has been difficult to validate that hypothesis. Multiple reconnection sites and different possible acceleration regions are too distant to be included in a single kinetic simulation and global hybrid simulations cannot describe electron acceleration.  To address this research problem we leverage our simulation capabilities by combining three different simulation techniques: global magnetohydrodynamic (MHD) simulations, large-scale kinetic (LSK) particle tracing simulations, and large-scale particle in cell (PIC) simulations.  First, we carry out an MHD simulation driven by upstream solar wind and interplanetary magnetic field conditions for a specific time interval featuring active magnetospheric reconnection.  Then we use an implicit PIC simulation of dayside reconnection with initial and boundary conditions from the MHD simulation.  Next, we follow suprathermal particles from the PIC simulation globally through the MHD fields using LSK to assess their transport into the magnetotail. A final step is to perform a PIC simulation embedded in the MHD simulation of magnetotail process including the suprathermal particles arriving from the dayside as determined from the LSK simulation.  Preliminary results indicate that particles energized by dayside reconnection are more likely to reach the magnetotail reconnection region. In addition, the development of enhanced high-energy tails in the particle distributions is promoted by previous energization steps during particle transport to the magnetotail reconnection region.</p>