A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface

The electrostatic charging environment inside lunar lava tubes was investigated in laboratory experiments using a glass tube exposed to a simulated solar wind flow. A conducting surface was attached at the entrance of the tube and biased to various negative potentials to study the electron shielding...

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Main Authors: S. Gopalakrishnan, X. Wang, M. Horányi
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Planetary Science Journal
Subjects:
Online Access:https://doi.org/10.3847/PSJ/ada6b0
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author S. Gopalakrishnan
X. Wang
M. Horányi
author_facet S. Gopalakrishnan
X. Wang
M. Horányi
author_sort S. Gopalakrishnan
collection DOAJ
description The electrostatic charging environment inside lunar lava tubes was investigated in laboratory experiments using a glass tube exposed to a simulated solar wind flow. A conducting surface was attached at the entrance of the tube and biased to various negative potentials to study the electron shielding effect on the charging conditions inside the tube. The electrical potential at the bottom of the glass tube was measured using a planar probe. It is shown that the bottom surface potential is positive and increases with the increasing ion beam energy, as well as with the increasing depth inside the tube, as a result of electron Debye shielding at the entrance and along the length of the tube due to the electron thermal motion. It is found that the bottom tube potential does not approach the ion kinetic energy even when the solar wind electrons are nearly fully shielded from entering the tube. We show that ion-generated secondary electrons from the sidewall of the tube partially neutralize the buildup of positive charges at the bottom of the tube. Our results provide insights into the plasma charging environment inside lunar lava tubes that may be used as natural habitats for future human exploration on the surface of the Moon.
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series The Planetary Science Journal
spelling doaj-art-5412c6d821d5483ebef8a42a04dfd8552025-02-03T16:21:40ZengIOP PublishingThe Planetary Science Journal2632-33382025-01-01623310.3847/PSJ/ada6b0A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar SurfaceS. Gopalakrishnan0https://orcid.org/0009-0008-1927-1659X. Wang1https://orcid.org/0000-0001-8472-7079M. Horányi2https://orcid.org/0000-0002-5920-9226NASA SSERVI’s Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT), University of Colorado Boulder , Boulder, CO 80303, USA; Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder , Boulder, CO 80303, USANASA SSERVI’s Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT), University of Colorado Boulder , Boulder, CO 80303, USA; Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder , Boulder, CO 80303, USANASA SSERVI’s Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT), University of Colorado Boulder , Boulder, CO 80303, USA; Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder , Boulder, CO 80303, USAThe electrostatic charging environment inside lunar lava tubes was investigated in laboratory experiments using a glass tube exposed to a simulated solar wind flow. A conducting surface was attached at the entrance of the tube and biased to various negative potentials to study the electron shielding effect on the charging conditions inside the tube. The electrical potential at the bottom of the glass tube was measured using a planar probe. It is shown that the bottom surface potential is positive and increases with the increasing ion beam energy, as well as with the increasing depth inside the tube, as a result of electron Debye shielding at the entrance and along the length of the tube due to the electron thermal motion. It is found that the bottom tube potential does not approach the ion kinetic energy even when the solar wind electrons are nearly fully shielded from entering the tube. We show that ion-generated secondary electrons from the sidewall of the tube partially neutralize the buildup of positive charges at the bottom of the tube. Our results provide insights into the plasma charging environment inside lunar lava tubes that may be used as natural habitats for future human exploration on the surface of the Moon.https://doi.org/10.3847/PSJ/ada6b0Solar windThe MoonSpace plasmasSurface compositionLunar surfaceSurface processes
spellingShingle S. Gopalakrishnan
X. Wang
M. Horányi
A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
The Planetary Science Journal
Solar wind
The Moon
Space plasmas
Surface composition
Lunar surface
Surface processes
title A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
title_full A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
title_fullStr A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
title_full_unstemmed A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
title_short A Laboratory Study of Plasma Charging Inside Lava Tubes on the Lunar Surface
title_sort laboratory study of plasma charging inside lava tubes on the lunar surface
topic Solar wind
The Moon
Space plasmas
Surface composition
Lunar surface
Surface processes
url https://doi.org/10.3847/PSJ/ada6b0
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AT sgopalakrishnan laboratorystudyofplasmacharginginsidelavatubesonthelunarsurface
AT xwang laboratorystudyofplasmacharginginsidelavatubesonthelunarsurface
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