March 13, 2009 - CCLDAS Particle-in-Cell Simulations of the Lunar Dusty Plasma Environment A. Poppe & M. Horányi Laboratory for Atmospheric and Space Physics.

March 13, 2009 - CCLDAS

Particle-in-Cell Simulations of the Lunar Dusty Plasma Environment

A. Poppe & M. Horányi

Laboratory for Atmospheric and Space Physics

Dept. of Physics, Univ. of Colorado at Boulder

March 13, 2009 - CCLDAS

Research Questions

• What are the properties of the lunar plasma environment due to photoelectron emission, exposure to solar wind, etc.?

• What are the required conditions for electrostatic dust charging, levitation and transport?

• How well do ongoing laboratory measurements reproduce the lunar environment?

March 13, 2009 - CCLDAS

Particle-in-Cell Code

• First model is 1-d, without dust particles– Goal is to characterize the properties of the

photoelectron sheath present on the dayside of the Moon

• Grard & Tunaley [1971] present analytical solutions to electron density, electric field and sheath thickness for three electron distributions

March 13, 2009 - CCLDAS

1-d PIC Results

Monokinetic electron velocity distribution (T=3eV)

March 13, 2009 - CCLDAS

1-d PIC Results

Rectangular electron velocity distribution (T=3eV)

March 13, 2009 - CCLDAS

1-d PIC Results

Maxwellian electron velocity distribution (T=3eV)

March 13, 2009 - CCLDAS

1-d PIC Results

• Define a more realistic photoelectron energy distribution (after Feuerbacher et al. 1972)

Emax = 6 eV

Eavg = 2.2 eV

March 13, 2009 - CCLDAS

1-d PIC Results

Feuerbacher et al., 1972 electron velocity distribution

March 13, 2009 - CCLDAS

Future Work

• Additions to the 1-d code:– Presence of solar wind ions/electrons– Dependence on emission current

• Development of 2-d code– Topography / Time-variation

• Eventual inclusion of dust particles

• Comparison with laboratory experiments