  Understanding the relationship among different emission components plays an
essential role in the study of particle acceleration and energy conversion in
solar flares. In flares where gradual and impulsive emission components can be
readily identified the impulsive emission has been attributed to non-thermal
particles. We carry out detailed analysis of H\alpha\ and X-ray observations of
a GOES class B microflare loop on the solar disk. The impulsive hard X-ray
emission, however, is found to be consistent with a hot, quasi-thermal origin,
and there is little evidence of emission from chromospheric footpoints, which
challenges conventional models of flares and reveals a class of microflares
associated with dense loops. H\alpha\ observations indicate that the loop lies
very low in the solar corona or even in the chromosphere and both emission and
absorption materials evolve during the flare. The enhanced H\alpha\ emission
may very well originate from the photosphere when the low-lying flare loop
heats up the underlying chromosphere and reduces the corresponding H\alpha\
opacity. These observations may be compared with detailed modeling of flare
loops with the internal kink instability, where the mode remains confined in
space without apparent change in the global field shape, to uncover the
underlying physical processes and to probe the structure of solar atmosphere.
