The effect of whistler waves on the electron distribution function is considered for the November 7, 1977, bow shock crossing. Order of magnitude estimates of the diffusion times due to whistler waves and to electrostatic noise shows that whistler waves are also effective in shaping the electron distribution function fe, causing pitch angle diffusion in the limit of low frequencies. A Monte Carlo simulation of the electron dynamics, which includes electrostatic as well as whistler random terms, is then set up. A study of the diffusion coefficients, together with the use of the experimental data on electromagnetic noise, allows us to assess spatial and velocity profiles for the random terms of the simulation. The moments of fe, including the perpendicular temperature and the heat flux densities, are reproduced satisfactorily by the numerical results. The resulting scenario for electron heating in quasi-perpendicular shocks can be described as follows: (1) the shock steady electric field in the deHoffman-Teller frame energizes the electrons, but the parallel temperature is too high and the perpendicular temperature too low, and a hole in fe is formed; (2) parallel diffusion due to the electrostatic noise fills the hole in fe and creates a flat-topped distribution, thus cooling the electrons, but the perpendicular temperature remains too low; (3) pitch angle diffusion due to whistler waves transfers energy from parallel to perpendicular, increasing the perpendicular temperature up to the observed values. ¿ American Geophysical Union 1993 |