Longitudinal magnetic tube wave fluxes in stars of low metallicity

Abstract

A modified theory of turbulence generation is combined with the magnetohydrodynamic equations to numerically compute the wave energies generated at the base of magnetic flux tubes for stars with effective temperatures ranging from T-eff = 3000 to 7000 K, gravity log g = 4.44 and with different metal abundances: solar, 0.1, 0.01 and 0.001 of solar metallicity. The results show that the effect of metallicity is very important for cool stars (T-eff < 5500 K). The current numerical approach allows for non-linear waves with large amplitudes and thus the obtained results for time-averaged wave energy fluxes are higher than those obtained by the analytical approach. For hot stars the effect is negligible. The computed energy fluxes are essential for constructing theoretical models of the magnetic chromosphere of low-metallicity stars. The maximum obtained wave energy flux for low-metallicity stars is about 7.3 x 10(8) erg cm(-2) s(-1).