Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radiation by a relativistic charged particle in self-wakefield in
  periodic structure   A new elementary mechanism of radiation due to the oscillatory character of a
radiation reaction force appearing when a relativistic charged particle moves
along a periodic structure without external fields is investigated. It is shown
that the non-synchronous spatial harmonics of Cherenkov-type radiation (CR) can
give rise to the oscillation of a particle which consequently generates
undulator-type radiation (UR). In the spectral region, where the diffraction of
generated waves is essential, the radiation manifests itself in the coherent
interference of CR and UR. A pure undulator -type radiation takes place only in
the wavelength range where the wave diffraction can be neglected. In the case
of coherent UR by a bunch of N electrons, the UR power is proportional to N in
the forth degree.

15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph