Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dust detection by the wave instrument on STEREO: nanoparticles picked up
  by the solar wind?   The STEREO/WAVES instrument has detected a very large number of intense
voltage pulses. We suggest that these events are produced by impact ionisation
of nanoparticles striking the spacecraft at a velocity of the order of
magnitude of the solar wind speed. Nanoparticles, which are half-way between
micron-sized dust and atomic ions, have such a large charge-to-mass ratio that
the electric field induced by the solar wind magnetic field accelerates them
very efficiently. Since the voltage produced by dust impacts increases very
fast with speed, such nanoparticles produce signals as high as do much larger
grains of smaller speeds. The flux of 10-nm radius grains inferred in this way
is compatible with the interplanetary dust flux model. The present results may
represent the first detection of fast nanoparticles in interplanetary space
near Earth orbit.

35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org