We show that, under Braginskii magneto-hydrodynamics, anti-parallel gradients in average ion charge state and electron temperature can be unstable to the growth of self-generated magnetic fields. The instability is analogous to the field-generating thermomagnetic instability, although it is driven by the collisional thermal force magnetic source term rather than the Biermann battery term. The gradient in ion charge state causes a gradient in collisionality, which couples with temperature perturbations to create a self-generated magnetic field. This magnetic field deflects the electron heat flux in a way that reinforces the temperature perturbation. The derived linearized growth rate, typically on hydrodynamic timescales, includes the resistive and thermal smoothing. It increases with large ion composition gradients and electron heat flux, conditions typical of the hohlraum walls or contaminant mix jets in inertial confinement fusion implosions. However, extended magneto-hydrodynamic simulations indicate that the instability is usually dominated and stabilized by the nonlinear Nernst advection, in a similar manner to the standard thermomagnetic instability.

中文翻译：

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等离子体成分梯度的热磁不稳定性

我们表明，在 Braginskii 磁流体动力学下，平均离子电荷态和电子温度的反平行梯度对自生磁场的增长可能不稳定。这种不稳定性类似于产生场的热磁不稳定性，尽管它是由碰撞热力磁源项而不是比尔曼电池项驱动的。离子电荷状态的梯度导致碰撞梯度，这与温度扰动相结合以产生自生磁场。该磁场以增强温度扰动的方式偏转电子热通量。导出的线性化增长率，通常在流体动力学时间尺度上，包括电阻平滑和热平滑。它随着大的离子组成梯度和电子热通量而增加，惯性约束聚变内爆中的空腔壁或污染物混合射流的典型条件。然而，扩展的磁流体动力学模拟表明不稳定通常由非线性能斯特平流控制和稳定，与标准热磁不稳定性类似。