Effects of the Lower Energy Cutoff Behavior on the Maser Emission Excited by Temperature Anisotropy

The electron-cyclotron maser emission (ECME) is one of the most important radio emission mechanisms in astrophysics. It has been extensively applied to various coherent radio-burst phenomena. Most discussions on the ECME suppose that the energetic electrons have an anisotropy distribution in the velocity space. However, observations from hard X-ray demonstrate that energetic flare-electrons frequently present a power-law distribution with a lower-energy cutoff. In this paper, we consider the rising rate of ECM instability driven by temperature anisotropy and by temperature anisotropy with low-energy cutoff behavior respectively. The results show that the lower-energy cutoff behavior has an important effect on the ECME driven by the temperature anisotropy.