CALET observations of galactic electrons in the heliosphere

The CALorimetric Electron Telescope(CALET) mission is proposed to measure galactic electrons and gamma rays on ISS/JEM for three years[1]. In this paper we report the purpose of this project in solar physics and the expected results from precise measurement of electron energy spectrum in the 1-100GeV energy range. The CALET measurement of long-term variations of the energy spectrum will produce a wealth of data to investigate electron propagation in the heliosphere. CALET does not distinguish positive charge from negative one. However, we can evaluate the charge sign dependence of solar modulation using correlation with the neutron monitors, since most particles are negative electrons in this energy range. Further we estimate transport parameters, mainly the energy dependence of diffusion coefficient in the heliosphere. CALET will also have a capability of measuring the short-term variation of around ten Forbush decreases(Fds) for three years. Precise measurements of the energy spectral variation of Fds will give a conclusion of the energy dependence of Fds.