On the distributions of photoelectrons over the illuminated part of the moon

Dusty plasmas over the Moon

“…The difference between the quantum yields presented in Walbridge (1973) and (Willis et al 1973) affects the calculation much more strongly than the variation of the work function which typically (for lunar regolith) is within the range of 5 to 6 eV. Indeed, the number density N 0 (near the lunar surface) and the temperature T e of photoelectrons corresponding to the quantum yield from Walbridge (1973) are of the order of 10 5 cm −3 and 0.1 eV, while those values calculated for the quantum yield from Willis et al (1973) are ∼ 10 2 − 10 3 cm −3 and ∼ 1 eV (Popel et al 2014). The above data are calculated for cos θ = 1, where θ is the subsolar angle.…”

“…Indeed, the number density N 0 (near the lunar surface) and the temperature T e of photoelectrons corresponding to the quantum yield from Walbridge (1973) are of the order of 10 5 cm −3 and 0.1 eV, while those values calculated for the quantum yield from Willis et al (1973) are ∼ 10 2 − 10 3 cm −3 and ∼ 1 eV (Popel et al 2014). The above data are calculated for cos θ = 1, where θ is the subsolar angle.…”

“…The Luna-25 and Luna-27 spacecrafts will detect dust particles and carry out optical observations of dust with the aid of piezoelectric shock sensors, electric field sensors, as well as stereo and surveillance cameras (Popel et al 2014). Location of the piezoelectric shock sensors and electric field sensors is supposed to be at the altitudes of 20 and 90 cm, while the cameras for optical observations will be placed on the top of the spacecrafts (approximately 2 m over the lunar surface).…”

“…As for the photoelectrons, an important parameter used in the calculations is the quantum yield determining the number of electrons knocked out from the surface by one photon (Popel et al 2014). The dependencies (Walbridge 1973;Willis et al 1973) of the quantum yield are usually used in studies of the plasma-dust system and/or photoelectrons near the surface of the Moon.…”

“…The electron temperature T e is independent of cos θ. Thus the quantum yield is a very important parameter requiring further refinement (Popel et al 2014).…”