Ryoya Sakata

Effects of Hot Oxygen Corona on Ion Escape From Venus‐Like Planets

Tetsuo Nishioka, K. Seki, Ryoya Sakata, N. Terada et autres

Abstract Due to the lack of a significant planetary magnetic field, the upper atmospheres of Venus‐like planets interact directly with the stellar wind. Therefore, thermal atomic oxygen in the thermosphere and hot oxygen in the corona produced by non‐thermal processes in the …

jp (code pays fourni par la source)

Asymmetrically Distributed Kelvin‐Helmholtz Instability at Venusian Magnetosphere

Maodong Yan, Jiuhou Lei, N. Terada, Binzheng Zhang et autres

Abstract The asymmetric distribution of Kelvin‐Helmholtz (KH) instability at Venusian ionopause is investigated using a multifluid model. Results show that KH instability distributes asymmetrically, preferentially developing in the −E (anti‐parallel to the interplanetary electric field) hemisphere. In the magnetosheath, solar wind H …

cn, jp, hk, us (code pays fourni par la source)

Atmospheric Escape Rates from Mars - If it Orbited an Old M-Dwarf Star

David A. Brain, O. Cohen, T. E. Cravens, Kevin France et autres

Atmospheric escape is an important process that influences the evolution of planetary atmospheres. A variety of physical mechanisms can contribute to escape from an atmosphere, including thermal escape, ion escape, photochemical escape, and sputtering. Here we estimate escape rates via each of …

Atmospheric Escape Rates from Mars - If it Orbited an Old M-Dwarf Star

David A. Brain, Ofer Cohen, T. E. Cravens, Kevin France et autres

Atmospheric escape is an important process that influences the evolution of planetary atmospheres. A variety of physical mechanisms can contribute to escape from an atmosphere, including thermal escape, ion escape, photochemical escape, and sputtering. Here we estimate escape rates via each of …

us, fr, jp, de, se, fi, gb, in, nl (code pays fourni par la source)

Effects of Hot Oxygen Corona on Ion Escape from Venus-like Planets

Tomoaki Nishioka, Kanako Seki, Ryoya Sakata, Naoki Terada et autres

This dataset contains the simulation results in the paper "Effects of Hot Oxygen Corona on Ion Escape from Venus-like Planets" submitted to Journal of Geophysical Research: Space Physics.

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Effects of stellar XUV spectra on atmospheric escape from a Mars-like planet orbiting inactive low-mass stars

Shotaro Sakai, Akifumi Nakayama, K. Seki, N. Terada et autres

ABSTRACT The influence of stellar extreme ultraviolet (XUV) spectral shape on ion escape from Mars-like planets is investigated using a multispecies single-fluid magnetohydrodynamic model coupled with thermospheric profiles derived from a one-dimensional model under various XUV conditions. Target stars include the Sun, …

jp, us, fr (code pays fourni par la source)

Exoplanet Atmospheric Escape Observations with the Habitable Worlds Observatory

Leonardo A. Dos Santos, Eric Lopez, L. Fossati, Shingo Kameda et autres

The Decadal Survey on Astronomy and Astrophysics 2020 highlights the importance of advancing research focused on discovering and characterizing habitable worlds. In line with this priority, our goal is to investigate how planetary systems evolve through atmospheric escape and to develop methods …

Comprehensive Comparison of Two Global Multis-species MHD Models of Mars

Wenyi Sun, Ryoya Sakata, Yingjuan Ma, K. Seki et autres

Understanding the interaction between Mars and the solar wind is crucial for comprehending the atmospheric evolution and climate change on Mars. To gain a comprehensive understanding of the Martian plasma environment, global numerical simulations are essential in addition to spacecraft observations. However, …

us, jp (code pays fourni par la source)

Study of Variation Mechanisms of the Martian Diffuse Aurora Based on Monte Carlo Simulations and MAVEN Observations

Taishin Okiyama, K. Seki, Yuki Nakamura, R. J. Lillis et autres

Abstract Martian diffuse auroras are ultraviolet emissions spread across the nightside of Mars caused by solar energetic particles (SEP), both electrons and protons. The nightside structures of induced and crustal magnetic fields are expected to affect the diffuse auroral emission profiles caused …

us, jp (code pays fourni par la source)

Simulation data presented by Okiyama, T., Seki, K., et al., 2024

Taishin Okiyama, Kanako Seki, Yuki Nakamura, Robert J. Lillis et autres

Supplemental data for Okiyama, T., Seki, K., et al., Study of variation mechanisms of the Martian diffuse aurora based on Monte Carlo simulations and MAVEN observations, accepted in Journal of Geophysical Research, 2024.

jp, us (code pays fourni par la source)

Comprehensive Comparison of Two Global Multi‐Species MHD Models of Mars

Wenyi Sun, Ryoya Sakata, Yingjuan Ma, K. Seki et autres

Abstract Understanding the interaction between Mars and the solar wind is crucial for comprehending the atmospheric evolution and climate change on Mars. To gain a comprehensive understanding of the Martian plasma environment, global numerical simulations are essential in addition to spacecraft observations. …

us, jp (code pays fourni par la source)

Effects of an Intrinsic Magnetic Field on Ion Escape From Ancient Mars Based on MAESTRO Multifluid MHD Simulations

Ryoya Sakata, K. Seki, Naoki Terada, Shotaro Sakai et autres

Abstract Ion escape has played a key role in atmospheric loss on ancient Mars due to intense solar activity. Under the existence of a strong global intrinsic magnetic field, as expected on ancient Mars, differential flows between different ion species can be …

jp (code pays fourni par la source)