In magnetically confined plasmas, the second derivative of the density is known to be related to the E × B velocity shear that rules the transitions to improved confinement regimes. In this work we present a cellular automata model for transport that includes diffusion and avalanche-like mechanisms controlled by critical parameters. Assuming the hypothesis that a strong negative value of the second derivative of the density reduces the strength of avalanches, the model shows the emergence of different confinement regimes that are found to be analogue to low (L), high (H) and very high (VH) confinement modes in real plasma. Transitions between such regimes can be controlled by the parameter representing the fuelling intensity. In particular, the model reproduces the formation of a pedestal during the transition from L to H confinement regimes, and shows hysteresis phenomena.
磁化等离子体中，密度的二阶导数已知与E×B速度剪切相关，后者控制着向约束改善模式的转变。本文提出了一个元胞自动机模型，用于描述输运过程，其中包含扩散机制以及由临界参数控制的类似雪崩的机制。假设密度的二阶导数为强负值时会减弱雪崩的强度，该模型展现出不同的约束模式，分别对应于实际等离子体中的低（L）模式、高（H）模式和甚高（VH）模式。这些模式之间的转变可以通过代表加料强度的参数来控制。特别地，该模型再现了从L模式向H模式转变过程中台基的形成，并表现出滞后现象。