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The plasma of the lower solar atmosphere consists of mostly neutral particles, whereas the upper solar atmosphere is mostly ionised particles and electrons. A shock that propagates upwards in the solar atmosphere therefore undergoes a transition where the dominant fluid is either neutral or ionised. An upwards propagating shock also passes a point where the sound and Alfven speed are equal. At this point the energy of the acoustic shock can separated into fast and slow components. How the energy is distributed between the two modes depends on the angle of magnetic field. The separation of neutral and ionised species in a gravitationally stratified atmosphere is investigated. The role of two-fluid effects on the structure of the shocks post-mode-conversion and the frictional heating is quantified for different levels of collisional coupling. Two-fluid numerical simulations are performed using the (Punderline{I}P) code of a wave steepening into a shock in an isothermal, partially-ionised atmosphere. The collisional coefficient is varied to investigate the regimes where the plasma and neutral species are weakly, strongly and finitely coupled. The propagation speeds of the compressional waves hosted by neutral and ionised species vary, therefore velocity drift between the two species is produced as the plasma attempts to propagate faster than the neutrals. This is most extreme for a fast-mode shock. We find that the collisional coefficient drastically changes the features present in the system, specifically the mode conversion height, type of shocks present, and the finite shock widths created by the two-fluid effects. In the finitely-coupled regime fast-mode shock widths can exceed the pressure scale height leading to a new potential observable of two-fluid effects in the lower solar atmosphere.
A magnetohydrodynamic (MHD) shock front can be unstable to the corrugation instability, which causes a perturbed shock front to become increasingly corrugated with time. An ideal MHD parallel shock (where the velocity and magnetic fields are aligned)
The role of slow-mode MHD shocks in magnetic reconnection is one of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, we investigate, using numerical simulations, t
Slow-mode shocks are important in understanding fast magnetic reconnection, jet formation and heating in the solar atmosphere, and other astrophysical systems. The atmospheric conditions in the solar chromosphere allow both ionised and neutral partic
We investigate the nature of dissipative instability appearing in a prominence planar thread filled with partially ionised plasma in the incompressible limit. The importance of partial ionisation is investigated in terms of the ionisation factor and
Compressional waves propagating in the partially ionised solar lower atmospheric plasmas can easily steepen into nonlinear waves, including shocks. Here we investigate the effect of weak dispersion generated by Hall currents perpendicular to the ambi