Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Experimental Study of Waveguide Coupled Microwave Heating with
  Conventional Multicusp Negative Ion Source   Negative ion production with conventional multicusp plasma chambers utilizing
2.45 GHz microwave heating is demonstrated. The experimental results were
obtained with the multicusp plasma chambers and extraction systems of the
RFdriven RADIS ion source and the filament driven arc discharge ion source
LIISA. A waveguide microwave coupling system, which is almost similar to the
one used with the SILHI ion source, was used. The results demonstrate that at
least one third of negative ion beam obtained with inductive RF-coupling
(RADIS) or arc discharge (LIISA) can be achieved with 1 kW of 2.45 GHz
microwave power in CW mode without any modification of the plasma chamber. The
co-extracted electron to H^- ratio and the optimum pressure range were observed
to be similar for both heating methods. The behaviour of the plasma implies
that the energy transfer from the microwaves to the plasma electrons is mainly
an off-resonance process.

11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: econ
13
The categories of this paper are: quant-ph