Question

Now consider the warm ionized medium (WIM). In a plasma (ionized gas), particles need not physically collide like billiard balls; they merely need to come close enough for electrical forces to scatter them. The electrical interaction energy between two elementrary charges e at separation r is U(r) = e2/4π0r , (2) where 0 is permittivity of the vacuum. A pair of charged particles will be strongly scattered if they come close enough to make U(r) comparable to their combined kinetic energy. (a) Given that the WIM has number density nWIM 106 m−3 and temperature T 10000 K, find the most probable velocities for protons (p) and electrons (e) in the WIM. (b) Using these velocities, estimate the scattering radii for protons and electrons in the WIM. Comapre your result to RH.

Answer 1