Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ion Acceleration - Target Normal Sheath Acceleration   Energetic ions have been observed since the very first laser-plasma
experiments.Their origin was found to be the charge separation of electrons
heated by thelaser, which transfers energy to the ions accelerated in the
field. The adventof ultra-intense lasers with pulse lengths in the femtosecond
regime resulted inthe discovery of very energetic ions with characteristics
quite different fromthose driven by long-pulse lasers. Discovered in the late
1990s, these ion beamshave become the focus of intense research worldwide,
because of their uniqueproperties and high particle numbers. Based on their
non-isotropic, beam-likebehaviour, which is always perpendicular to the
emitting surface, theacceleration mechanism is called target normal sheath
acceleration (TNSA). Weaddress the physics of the mechanism and its dependence
on laser and targetparameters. Techniques to explore and diagnose the beams, to
make them usefulfor applications, are also addressed.

25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
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The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
1
The categories of this paper are: cs