  The effect of a DC electric field on the longitudinal resistance of highly
mobile two dimensional electrons in heavily doped GaAs quantum wells is studied
at different magnetic fields and temperatures. Strong suppression of the
resistance by the electric field is observed in magnetic fields at which the
Landau quantization of electron motion occurs. The phenomenon survives at high
temperature where Shubnikov de Haas oscillations are absent. The scale of the
electric fields essential for the effect is found to be proportional to
temperature in the low temperature limit. We suggest that the strong reduction
of the longitudinal resistance is the result of a nontrivial change in the
distribution function of 2D electrons induced by the DC electric field.
Comparison of the data with recent theory yields the inelastic electron-electon
scattering time $\tau_{in}$ and the quantum scattering time $\tau_q$ of 2D
electrons at high temperatures, a regime where previous methods were not
successful.
