Research goals

  • To determining chromospheric heating mechanisms. The chromosphere hosts shock waves and current layers at any moment of time. These perturbations are consequences of waves excited at photospheric level. Ion-neutral effects provide very effective mechanisms for dissipation of currents produced by waves. They also produce new regimes, as multi-fluid nature of shock wave fronts. Our objective is to quantify the heating mechanisms associated to dissipation of chromospheric waves and shocks due to ion-neutral interactions in a frame of a precise two-fluid theory.
  • To understanding the destabilisation mechanisms of solar prominences. Prominences are blobs of chromospheric plasma suspended for days or months in the solar corona, and thermally insulated from it by the magnetic field. The prominences are kept stable due to magnetic tension forces. The neutrals composing prominence material only feel this force through the (weak) collisional coupling to the ions. PI2FA will allow us to gain insight on how the presence of neutrals affects the overall stability of the prominence structure and helps producing prominence eruptions.
  • To create realistic multi-dimensional multi-fluid models of the solar chromosphere. Three-dimensional magneto-convection models of the solar atmosphere have been proved to be a valuable tool to advance in our understanding about numerous magnetohydrodynamic processes. We challenge to create multi-fluid magneto-convection models of the chromosphere. These models will include altogether complex interactions down to smallest scales and allow direct comparison to observations, as a way to prepare our community for the coming 4-meter class telescopes EST and DKIST.


Methodology and working plan

  • Work-Package 1: Development and testing of the multi-fluid code. The two presently existing branches of the MANCHA code (the single-fluid one with the generalized Ohm’s law, and the two-fluid one for hydrogen plasma) are used as a starting point in developing the multi-fluid code for the solar mixture in WP1, employing the mathematical formalism by Khomenko et al. PhPl, 21, 092901, 2014.
  • Work-Package 2: Chromospheric energy budget. The purpose of the WP2 is to evaluate the energy deposition on the chromosphere due to interaction between ionised and neutral fluids. We will perform simulations of waves, instabilities and reconnection, using the multi-fluid code.
  • Work-Package 3: Two-fluid magneto-convection simulations of the photosphere and chromosphere. We will construct time-dependent two-fluid magneto-convection models, where the flows, waves and currents will be generated self-consistently by fluid motions and dissipated by non-ideal effects, allowing the plasma, magnetic field, and radiation to interact.
  • Work-package 4: Life cycle and stability of partially ionised prominences. Using the two-fluid code, we will study the importance of ion-neutral interactions in the propagation of waves, non-linear development of instabilities, and reconnection, aiming at clarifying the question of the prominence stability.
  • Work-package 5: Maximising the impact of current and future solar observational facilities. The team of the project will perform spectropolarimetric diagnostics based on two-fluid magneto-convection simulations, using the spectral synthesis codes.