  Through a detailed theoretical analysis of the local emission at
millimeter,sub-millimeter and infrared wavelength regimes (from \~ 10 GHz up to
\~ 10 THz), we found that, associated with the temperature minimum, there is an
optically thin cavity surrounded by two regions of high local emissivity. We
call this structure the Chromospheric Solar Millimeter Cavity (CSMC). In order
to search for traces of this cavity in the available radio observations on the
solar limb, we have developed a robust method to associate the radiation at
different heights with the observed brightness temperatures. We foresee that
this approach will allow us to determine the relationship between the CSMC and
the solar limb brightening.
