“…For the corresponding Navier-Stokes system, Xin [Xin98] proved that smooth solution will blow up in finite time in the whole space when the initial density has compact support, while Rozanova [Roz08] showed similar results for rapidly decreasing initial density. Fan-Jiang-Ou [FJO10], Sun-Wang-Zhang [SWZ11] and Suen [Sue20c] established some blow-up criteria for the classical solutions to 3D compressible flows, which were further extended by Lu-Du-Yao [LDY12] for MHD system. For the isothermal case when P (ρ) = Kρ for some K > 0, it was proved in [Sue13a,Sue15] that without vacuum in the initial density, when the density and magnetic field are essential bounded, the smooth solutions to (1.1)-(1.4) can be extended globally in time.…”