Browsing by Author "Alho, Markku"

The localized, crustal magnetic fields on the Moon show complex interactions with the impinging solar wind. Understanding these interactions aid in characterizing the lunar plasma and dust environment, in developing advanced remote imaging techniques for airless bodies such as the Moon and Mercury, and in comprehending the basic plasma processes of plasma environments and phenomena on the Hall physics scale. In this work a lunar magnetic anomaly is modeled in the mesoscale of hundreds of kilometers with 100 nT surface field anomaly. A numerical hybrid plasma model is employed, in which ions are treated as fully kinetic macroparticles, with electrons providing a massless, charge-neutralizing fluid. The effects of electron currents in these environments are discussed, and results of the effect of the interplanetary magnetic field conditions on the minimagnetosphere are presented in three cases: Open, closed, nominal. Results for three different impinging solar wind velocities in the nominal case are presented. The results are compared with satellite observations and are found to reproduce observations of proton deceleration and reflection by anti-moonward electric field. The model is shown to reproduce observed ENA emission from the lunar surface, with predictions on solar wind-depentant features. Model development by the author is presented with regards to the convergence and stability of the numerical scheme, especially in terms of dealing with a fast whistler mode. Considerations on the validity of the results are presented, with the conclusion of reasonable confidence in the results, with suggested improvements to the model brought forwards.