Abstract Details
Abstracts
Author: Harry G. Dudding
Requested Type: Consider for Invited
Submitted: 2025-02-21 09:48:01
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Contact Info:
UKAEA (United Kingdom Atomic Energy Authority)
Culham Campus
Abingdon, Oxfordshire OX14 3DB
UK
Abstract Text:
Mathematical models in plasma physics often rely on a priori assumptions regarding the relative importance of terms within the Vlasov-Maxwell system of equations. While these assumptions simplify our analysis, they can also restrict the model’s validity, such as obscuring the interplay between the various regimes of plasma physics. In this work, an application of the method of multiple scales (MMS) [1, 2] to the Vlasov-Maxwell system is presented, constructing a uniformly valid hierarchy of equations for general plasma dynamics. Unlike conventional approaches, the MMS framework avoids fixed assumptions about the ordering of physical parameters relative to the expansion parameter through the introduction of independent fast- and slow-scale coordinates in space and time. The additional degrees of freedom resulting from these new coordinates allow for the systematic elimination of secular terms, yielding an explicit Reynolds-like turbulence average. At first order the kinetic MHD-like system is obtained, featuring new terms originating from the retention of finite charge effects, as well as possessing a particularly simple mathematical form due to the use of a novel velocity coordinate and the elimination of the parallel electric field from the system. The inclusion of kinetic MHD dynamics is seen to consistently carry forward to higher orders, including to the gyrokinetic-like equations at second order, opening a possible pathway to a self-consistent description of these two regimes.
[1] Nayfeh A.H. 2000 Perturbation Methods (John Wiley & Sons)
[2] Bender C.M., Orszag S.A. 1999 Advanced Mathematical Methods for Scientists and Engineers: Asymptotic Methods and Perturbation Theory (Springer)
Characterization: 4.0
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