  We present near-infrared (2.5 - 5.0 um) spectra of shocked H2 gas in the
supernova remnant IC 443, obtained with the satellite AKARI. Three shocked
clumps-known as B, C, and G-and one background region were observed, and only
H2 emission lines were detected. Except the clump B, the extinctioncorrected
level population shows the ortho-to-para ratio of ~ 3.0. From the level
population of the clumps C and G-both AKARI's only and the one extended with
previous mid-infrared observations-we found that the v = 0 levels are more
populated than the v > 0 levels at a fixed level energy, which cannot be
reproduced by any combination of H2 gas in Local Thermodynamic Equilibrium. The
populations are described by the two-density power-law thermal admixture model,
revised to include the collisions with H atoms. We attributed the lower
(n(H2)=10^(2.8-3.8) cm-3) and higher (n(H2)=10^(5.4-5.8) cm-3) density gases to
the shocked H2 gas behind C-type and J-type shocks, respectively, based on
several arguments including the obtained high H I abundance n(H I)/n(H2)=0.01.
Under the hierarchical picture of molecular clouds, the C-type and J-type
shocks likely propagate into "clumps" and "clouds" (interclump media),
respectively. The power-law index b of 1.6 and 3.5, mainly determined by the
lower density gas, is attributed to the shock-velocity diversity, which may be
a natural result during shock-cloud interactions. According to our results, H2
v = 1 - 0 S(1) emission is mainly from J-shocks propagating into interclump
media. The H2 emission was also detected at the background region, and this
diffuse H2 emission may originate from collisional process in addition to the
ultraviolet photon pumping.
