2013MNRAS.433.2018B

Free energy, internal energy and specific heat for each of the three phonon spectrum branches of a magnetized Coulomb crystal with body-centred cubic lattice are calculated by numerical integration over the Brillouin zone in the range of magnetic fields B and temperatures T, such that 0 ≤ ωB/ωp ≤ 103 and 10-4 ≤ T/Tp ≤ 104. In this case, ωB is the ion cyclotron frequency, ωp and Tp are the ion plasma frequency and plasma temperature, respectively. The results of numerical calculations are approximated by simple analytical formulas. For illustration, these formulas are used to analyse the behaviour of the heat capacity in the crust of a neutron star with strong magnetic field. Thermodynamic functions of magnetized neutron star crust are needed for modelling various observational phenomena in magnetars and high magnetic field pulsars.