(Proposal ID) S11B-073

(PI) Uno, Takeru

(Proposal Title)
Jovian H_3^+ and H_2 auroras: Energy transfers between neutral and 
plasma (retry)

(Abstract)
We propose the first reliable measurement of the brightness, temperature, and 
velocity distributions of Jovian plasma and neutral upper atmospheres. This 
region emits the infrared aurora in 2-4 micron from H_3^+ (plasma) and H_2 
(neutral). Through these lines, we can get the information of energy 
injections (by ionospheric electric field and Joule heating) into and momentum 
transfers (by collisions) between plasmas and neutrals. In a previous 
observation, the morphological differences between neutral and plasma aurora 
is identified. It shall be explained by the energy input and transfer 
processes in the upper atmospheres, which is the key of the connection between 
the planetary rotation and the magnetospheric activities. The wide spectral 
coverage, high spectral resolution, and the high sensitivity of SUBARU/IRCS 
first enable us the simultaneous measurement of multiple H_3^+ and H_2 emission
 lines with enough spatial and spectral resolutions. From the results, we will 
derive the origin of the difference in the spatial distributions of neutral 
and plasma auroras, supported by temperature and velocity field profiles. It 
will tell us the heating and energy transfer processes which connects the 
Jovian magnetosphere - ionosphere - thermosphere coupling system.