This study investigates the density distributions of hydrogen ( \(\mathrm {H^0}\) and \(\mathrm {H^+}\) ) and lithium ( \(\mathrm {Li^0}\) , \(\mathrm {Li^+}\) , \(\mathrm {Li^{2+}}\) , and \(\mathrm {Li^{3+}}\) ) atoms and ions in a magnetized plasma exposed to a liquid lithium surface, and evaluates the potential for magnetohydrodynamic (MHD) instability triggered by pressure variations in the plasma. The physical model employs multiple reaction rate equations for various species and charge states, including net ionization and recombination to describe density distributions. MHD stability is assessed using the energy principle associated with pressure gradients. The analysis is conducted under simplified conditions neglecting curvature and time variations in plasma temperature and toroidal magnetic field. The results strongly suggest that under high central electron temperature, the electron density and total pressure in a plasma with a liquid lithium surface peak in the core–edge transition region. This leads to a steep negative radial pressure gradient, in which a pressure-driven instability is mitigated. This simplified study demonstrates that pressure-driven instability in the edge region can be avoided if an optimal balance is maintained between central electron temperature and vapor flux from the liquid lithium surface.
