Abstract
The Sun's chromosphere, which is the atmospheric layer located between the solar surface (photosphere) and the solar corona, holds the key to comprehend why the corona is thousands of times hotter than the Sun's surface. Recently, it became possible to observe the chromosphere at millimetre wavelengths with the Atacama Large Millimeter/sub-millimeter Array (ALMA), a radio interferometer, at unprecedented high spatial and temporal resolution.
This thesis focuses on the analysis of solar ALMA observations with the aim to characterize the physical processes that provide the energy required to sustain the high temperatures in the solar atmosphere. In this regard, ALMA provides new observations of the small-scale structure of the solar chromosphere and the dynamics of waves, which are essential for the transport of energy and thus the heating of the solar atmosphere. To this end, hundreds of small bright features were analyzed in the observations, finding that they could be associated with magnetohydrodynamic waves capable of supplying relevant energy to the chromosphere and corona. In addition, the propagation of waves between two layers of the chromosphere was probed using a novel mode of processing ALMA observations. The results presented here show the diagnostic potential of ALMA to observe and study small-scale phenomena in the chromosphere as a step forward in understanding the enigmatic coronal heating problem.