  The forces on individual electrons in an unscreened nondegenerate electron
fluid, due to electron density fluctuations, have been calculated using Monte
Carlo simulations and determined experimentally over a broad range of the
plasma parameter Gamma. The experimental results are obtained from the
magnetoconductivity sigma(B) measured for electrons on liquid helium below 1 K
for B \leq 8 T. The magnitude and density dependence of sigma(B) are explained
by the many-electron theory of magnetotransport. The internal electric fields
found from the experiments are in excellent agreement with the simulations.
