STRONG DOUBLE-LAYERS, EXISTENCE CRITERIA, AND ANNIHILATION - AN APPLICATION TO SOLAR-FLARES

We present some conditions for the stability of a strong double layer in a warm, current-carrying plasma, which can be extended into the rel ativistic regime. We apply a model for plasma heating by the electron beam emitted from the double layer and show that this leads to a finit e life time of the double layer. We also show that the radio emission accompanying this process can well describe the observed phenomena in Type I radio bursts using a direct emission mechanism, not involving L angmuir waves.