Spontaneous reduction of the heat conductivity by a temperature gradient-driven instability in electron-ion plasmas

We have shown that there exist low-frequency growing modes driven by a global temperature gradient in electron and ion plasmas, by linear perturbation analysis within the frame work of plasma kinetic theory. The driving force of the instability is the local deviation of the distribution function from the Maxwell-Boltzmann due to a global temperature gradient. Our results suggest that the realization of the global thermal equilibrium is postponed by the local instability which is induced for quicker realization of local thermal equilibrium state in plasmas. The instability provides a new possibility to create and amplify cosmic magnetic fields without the seed for a magnetic field.