论文标题
指导中心运动的近似对称性
Approximate symmetries of guiding-centre motion
论文作者
论文摘要
除了能量和磁矩外，准对称性对带电的粒子运动产生了第三个不变性。我们在一阶引导中心运动的近似对称性水平上解决了准对称。我们发现，如果人们坚持对称性纯粹是空间的，则领先顺序的条件与精确的准对称条件相同。我们还概括以实现近似的相位对称性，并得出较弱的条件。后者恢复了“弱的准对称”为子案例，因此我们证明它仅是领先顺序的，但也意味着它存在更广泛的独立近似保守量。最后，我们证明磁液压学施加了准对称的领先顺序。
Quasisymmetry builds a third invariant for charged-particle motion besides energy and magnetic moment. We address quasisymmetry at the level of approximate symmetries of first-order guiding-centre motion. We find that the conditions to leading order are the same as for exact quasisymmetry if one insists that the symmetry is purely spatial. We also generalise to allow for approximate phase-space symmetries, and derive weaker conditions. The latter recover "weak quasisymmetry" as a subcase, thus we prove it is spatial only to leading order, but also that it implies the existence of a wider class of independent approximate conserved quantities. Finally, we demonstrate that magnetohydrostatics imposes quasisymmetry to leading order.
