Please check out these links for a discussion of VLF signatures from meteors:
Beech M, Brown P & Jones J, VLF detection of fireballs, Earth Moon & Planets (Netherlands), 68 (1995) 181.
Beech M, & Foschini, L., Leonid Electrophonic Bursters, Astronomy and Astrophysics 367, (2001), 1056.
Beech M, & Foschini, L., A space charge model for electrophonic bursters, Astronomy and Astrophysics 345 (1999) L27
Rault, Jean-L., On the potential meteors ELF/VLF radiations Perseids 2009 campaign. (2010)