Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exceptional Point of Degeneracy in Backward-Wave Oscillator with
  Distributed Power Extraction   We show how an exceptional point of degeneracy (EPD) is formed in a system
composed of an electron beam interacting with an electromagnetic mode guided in
a slow wave structure (SWS) with distributed power extraction from the
interaction zone. Based on this kind of EPD, a new regime of operation is
devised for backward wave oscillators (BWOs) as a synchronous and degenerate
regime between a backward electromagnetic mode and the charge wave modulating
the electron beam. Degenerate synchronization under this EPD condition means
that two complex modes of the interactive system do not share just the
wavenumber, but they rather coalesce in both their wavenumbers and eigenvectors
(polarization states). In principle this new condition guarantees full
synchronization between the electromagnetic wave and the beam's charge wave for
any amount of output power extracted from the beam, setting the threshold of
this EPD-BWO to any arbitrary, desired, value. Indeed, we show that the
presence of distributed radiation in the SWS results in having high-threshold
electron-beam current to start oscillations which implies higher power
generation. These findings have the potential to lead to highly efficient BWOs
with very high output power and excellent spectral purity.

16
The categories of this paper are: stat
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th