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arXiv 2212.13293math.DS
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关于慢-快哈密顿系统共振时的相位

On phase at a resonance in slow-fast Hamiltonian systems

Yuyang Gao, Anatoly Neishtadt, Alexey Okunev

摘要:

我们考虑一个具有一个快角变量(快相位)的慢-快哈密顿系统,其频率在慢变量空间中的某个表面(共振表面)上为零。这种形式的系统出现在高频静电波影响下的不均匀磁场中带电粒子动力学的研究中。在快相系统上平均的轨迹穿过谐振表面。快速相位使$\sim \frac {1}{\varepsilon}$在到达谐振表面之前转弯($\varepsilon$是问题的小参数)。早先在研究带电粒子动力学的背景下,基于启发式考虑,推导出了到达共振时相位值的渐近公式,但没有对其准确性进行任何估计。我们提供了一个严格的推导这个公式,并证明其准确性是$O(\sqrt \varepsilon)$(对数校正)。数值表明,这种精度估计是最佳的。

英文摘要:

We consider a slow-fast Hamiltonian system with one fast angular variable (a fast phase) whose frequency vanishes on some surface in the space of slow variables (a resonant surface). Systems of such form appear in the study of dynamics of charged particles in inhomogeneous magnetic field under influence of a high-frequency electrostatic waves. Trajectories of the averaged over the fast phase system cross the resonant surface. The fast phase makes $\sim \frac {1}{\varepsilon}$ turns before arrival to the resonant surface ($\varepsilon$ is a small parameter of the problem). An asymptotic formula for the value of the phase at the arrival to the resonance was derived earlier in the context of study of charged particle dynamics on the basis of heuristic considerations without any estimates of its accuracy. We provide a rigorous derivation of this formula and prove that its accuracy is $O(\sqrt \varepsilon)$ (up to a logarithmic correction). Numerics indicate that this estimate for the accuracy is optimal.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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