  The spatial-frequency coverage of a radio interferometer is increased by
combining samples acquired at different times and observing frequencies.
However, astrophysical sources often contain complicated spatial structure that
varies within the time-range of an observation, or the bandwidth of the
receiver being used, or both. Image reconstruction algorithms can been designed
to model time and frequency variability in addition to the average intensity
distribution, and provide an improvement over traditional methods that ignore
all variability. This paper describes an algorithm designed for such
structures, and evaluates it in the context of reconstructing three-dimensional
time-varying structures in the solar corona from radio interferometric
measurements between 5 GHz and 15 GHz using existing telescopes such as the
EVLA and at angular resolutions better than that allowed by traditional
multi-frequency analysis algorithms.
