Theoretical Models of the Solar Chromosphere, Transition Region and Wind

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The investigators will determine which heating mechanisms dominate in different regions of the solar atmosphere. The main effort is to construct novel theoretical models that will describe the entire solar atmosphere. Observations show that the solar atmosphere can be divided into three main regions: chromosphere, transition region and corona. In each of these regions the temperature increases with height and reaches its maximum in the corona, where both X-ray emission and the solar wind originate. One of the most important, and still unsolved, problems in solar physics is to identify the basic physical processes that are responsible for this heating. There are at least two general classes of models of this heating. In the first class, the solar atmosphere is heated by hydrodynamic (mainly acoustic) or magnetohydrodynamic (MHD) waves, and it is assumed that these waves are generated by turbulent motions in the solar convection zone. In the second class, dissipation of currents generated by photospheric motions of solar magnetic fields is the primary source of energy for the heating. Despite the vast amount of solar data collected during numerous ground observations and space missions, and significant theoretical efforts, it is still unclear how different regions of the solar atmosphere actually are heated. The investigators will take a novel approach to this problem by constructing theoretical models that describe the entire solar atmosphere. By comparing these models with observations, they will determine which heating mechanisms dominate in different regions of the solar atmosphere. Their work will be important in ongoing efforts to understand the principal energy sources for the solar atmosphere and the basic physical processes responsible for creating the heliosphere.