Plasma heating by a relativistic electron beam

We report measurements on the heating of a hydrogen plasma by means of a relativistic electron beam — The beam parameters are: V
b
=600 kV, I
b
= 5 kA, τ
max
= 400 ns. The plasma density was varied between 1 × 10
¹⁹
m
⁻³
and 3 × 10
²⁰
m
⁻³
. We observed maximum heating at n
e
=8 × 10
¹⁹
m
⁻³
. The corresponding electron temperature is 200 eV.