Premium
Solar Wind Access to Grains in the Upper Layer of Regolith
Author(s) -
Kulchitsky Anton V.,
Hurley Dana M.,
Johnson Jerome B.,
Duvoy Paul X.,
Zimmerman Michael
Publication year - 2018
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2017je005392
Subject(s) - regolith , monte carlo method , solar wind , penetration depth , exponential function , computational physics , distribution function , distributed ray tracing , materials science , physics , ray tracing (physics) , astrobiology , optics , thermodynamics , plasma , mathematics , mathematical analysis , statistics , quantum mechanics
The surface of the Moon is exposed to the solar wind and the particles can reach a few average grains deep into the regolith. This work examines the depth of penetration of solar wind particles in lunar regolith using equations derived from analytical, Monte Carlo, and ray tracing techniques and discrete element method simulations. It is shown that the process can be approximately described using an exponential distribution function starting from some small depth with parameters depending on void ratio, solar wind incidence angle, and regolith grain size distribution. The proton implantation rate into the regolith as a function of depth is proposed with the coefficients computationally derived from Monte Carlo simulations of proton implantation process.