  Recent three-dimensional radiation hydrodynamic simulations by Wedemeyer et
al. (2004) suggest that the solar chromosphere is highly structured in space
and time on scales of only 1000 km and 20-25 sec, resp.. The resulting pattern
consists of a network of hot gas and enclosed cool regions which are due to the
propagation and interaction of shock fronts. In contrast to many other
diagnostics, the radio continuum at millimeter wavelengths is formed in LTE,
and provides a rather direct measure of the thermal structure. It thus
facilitates the comparison between numerical model and observation. While the
involved time and length scales are not accessible with todays equipment for
that wavelength range, the next generation of instruments, such as the Atacama
Large Millimeter Array (ALMA), will provide a big step towards the required
resolution. Here we present results of radiative transfer calculations at mm
and sub-mm wavelengths with emphasis on spatial and temporal resolution which
are crucial for the ongoing discussion about the chromospheric temperature
structure.
