Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of the microbunching instability in a mid-energy electron linac   Microbunching instability usually exists in the linear accelerator (linac) of
a free electron laser (FEL) facility. If it is not controlled effectively, the
beam quality will be damaged seriously and the machine will not operate
properly. In the electron linac of a soft X-Ray FEL device, because the
electron energy is not very high, the problem can become even more serious. As
a typical example, the microbunching instability in the linac of the proposed
Shanghai Soft X-ray Free Electron Laser facility (SXFEL) is investigated in
detail by means of both analytical formulae and simulation tools. In the study,
a new mechanism of introducing random noise into the beam current profile as
the beam passes through a chicane-type bunch compressor is proposed. The
higher-order modes that appear in the simulations suggest that further
improvement of the current theoretical model of the instability is needed.

13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an