An Overview of Charging of Large Space Structures in Polar Orbit,

This paper gives an overview of some of the important questions regarding charging effects on large space structures in the polar ionosphere. The ionosphere as a rule is a rather benign environment as far as charging of spacecraft is concerned. The ionospheric plasma ia relatively cool and dense in comparison with other plasmas in space. The plasma density ranges from values on the order of 1000000cu cm down to values as low as or even below 100cu cm, with temperatures well below 1 eV 11600 K. However, there can be large fluxes of energetic electrons in the polar ionosphere. This subject is a matter of concern because these auroral fluxes could charge a spacecraft to large potentials.