Empirical determination of the energy loss rate of accelerated electrons in a well-observed solar flare

We present electron images of an extended solar flare source, deduced from RHESSI hard X-ray imaging spectroscopy data. We apply the electron continuity equation to these maps in order to determine empirically the form of the energy loss rate for the bremsstrahlung-emitting electrons. We show that this form is consistent with an energy transport model involving Coulomb collisions in a target with a temperature of about 2 × 107 K, with a continuous injection of fresh deka-keV electrons at a rate of approximately 10–2 electrons s–1 per ambient electron.