Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Numerical investigations of a cylindrical Hall thruster   A new 3 dimensional Particle-in-Cell code was applied to simulate the
operation of a 100 W CHT thruster. In the simulation a spoke moving with a
velocity of about 0.8 cm/\mu s was observed. The initial position of the spoke
was found to be strongly correlated with the cathode placement. The simulation
has shown that the depletion of neutral gas can lead to azimuthal asymmetry of
the discharge and possibly to the spoke phenomenon.

25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio