Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mapping lightning in the sky with a mini array   Mini arrays are commonly used for infrasonic and seismic studies. Here we
report for the first time the detection and mapping of distant lightning
discharges in the sky with a mini array. The array has a baseline to wavelength
ratio $\sim$4.2 ${ \cdot}$ $10^{-2}$ to record very low frequency
electromagnetic waves from 2 to 18 kHz. It is found that the mini array detects
$\sim$69 lightning pulses per second from cloud-to-ground and in-cloud
discharges, even though the parent thunderstorms are $\sim$900-1100 km away and
a rigorous selection criterion based on the quality of the wavefront across the
array is used. In particular, lightning pulses that exhibit a clockwise phase
progression are found at larger elevation angles in the sky as the result of a
birefringent subionospheric wave propagation attributed to ordinary and
extraordinary waves. These results imply that long range lightning detection
networks might benefit from an exploration of the wave propagation conditions
with mini arrays.

12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin