In the project, we have considered two physical models for configurations in the solar corona. The first configuration is for closed coronal loops, and the other configuration is for open coronal plumes.
In the first configuration we have considered active region coronal loops, which are magnetically closed on both ends. After driving the loops with transverse waves, instabilities are formed, that resemble very much water waves generated by wind, i.e. the so-called Kelvin-Helmholtz instability. Through this instability, smaller and smaller scales are created in the magnetic field, and eventually the plasma is heated. In our current simulations, we obtain significant plasma heating, of up to 500000 degrees, comparable to radiative energy losses in the solar corona. Our latest results show a loop that can be heated by transverse wave driven turbulence, even in the presence of radiative losses. We have used the theoretical results in this project to formulate equations for simulating the whole solar coronal volume with this heating mechanism, in a parametrised way.
In the second configuration, we study the open magnetic field regions near the poles of the Sun. There the "loops" are magnetically closed on one end, but open on the other end. Thus, the generated waves do not return and continue going into outer space. Still, we have found a new way to also generate an instability, which we have called uniturbulence. We have studied how our simulations compare to the observations. There we have shown that our simulations can explain the correlation between the width of a spectral line and the Doppler shift can be self-consistently generated. We have obtained an analytic function that describes the heating in this case. This combines with the theoretical model for the first configuration to model the heating in the open field regions of the solar corona.
