Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Charged particle motion in weakly varying electromagnetic fields: A
  multi-scale approach   The motion of charged particles in weakly varying electromagnetic fields is
described using a perturbation method. This provides a systematic and
physically transparent description of the particle motion on fast and slow
spatio-temporal scales, associated with gyration and drift motions,
respectively. A detailed discussion is given of the guiding center concept and
the non-inertial frame of reference. An algebraic expression is obtained for
the drift motion across the magnetic field, while a differential equation
describes the particle motion along the field. The fictitious forces and
associated energy transfer between gyration and drift motion parallel and
perpendicular to the magnetic field are described. The relation between
conservation of magnetic moment and angular momentum is elucidated.

9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn