The features of the irreversible propagation of thermal instabilities in composite superconductors are investigated under different cooling conditions (intensive and non-intensive) during magnetic flux creep. The analysis was performed with two models of the voltage-current characteristic of a superconductor: an ideal model having a jump-like transition from a superconducting state to a normal, and an actual model described by a power equation. The non-stationary and quasi-stationary (autowave) propagation velocities of the thermal instabilities along the composite are calculated taking into account the nonlinear properties of the composite and the refrigerant. The calculations of the propagation velocities of thermal instability are performed for both subcritical and supercritical currents. It is shown that the autowave velocities of the irreversible propagation of the thermal instability in the intensively cooled composite may only be positive since the conditions of the equal-area theorem may not be fulfilled. It is proved that the propagation of thermal instabilities in the composite superconductors is similar to the diffusion phenomena occurring in chain reactions of the exploding type.

在磁通量蠕变的不同冷却条件下（强和非强），研究了复合超导体中热不稳定性的不可逆传播特征。用超导体的电压-电流特性的两个模型进行分析：具有从超导状态到法线的跳跃状跃迁的理想模型和由功率方程描述的实际模型。考虑到复合材料和制冷剂的非线性特性，计算了沿复合材料的热不稳定性的非平稳和准静态（自动波）传播速度。对亚临界电流和超临界电流都进行了热不稳定性传播速度的计算。结果表明，由于无法满足等面积定理的条件，在强烈冷却的复合材料中热不稳定性的不可逆传播的自动波速度可能只是正的。事实证明，复合材料超导体中热不稳定性的传播与爆炸型链式反应中发生的扩散现象相似。