Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Communication through plasma sheaths   We wish to transmit messages to and from a hypersonic vehicle around which a
plasma sheath has formed. For long distance transmission, the signal carrying
these messages must be necessarily low frequency, typically 2 GHz, to which the
plasma sheath is opaque. The idea is to use the plasma properties to make the
plasma sheath appear transparent.

34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas