Editing Ball lightning (section)

=== Rydberg matter concept ===
Manykin et al. have suggested atmospheric [[Rydberg matter]] as an explanation of ball lightning phenomena.<ref>{{cite journal | last1 = Manykin | first1 = E. A. | last2 = Ojovan | first2 = M. I. | last3 = Poluektov | first3 = P. P. | s2cid = 96732651 | editor1-last = Samartsev | editor1-first = Vitaly V | doi = 10.1117/12.675004 | title =Rydberg matter: Properties and decay| journal = Proceedings of the SPIE | volume = 6181 | series = SPIE Proceedings | pages = 618105–618105–9 | year = 2006 | bibcode = 2006SPIE.6181E..05M }}</ref> Rydberg matter is a condensed form of highly excited atoms in many aspects similar to electron-hole droplets in semiconductors.<ref>{{cite journal | last1 = Norman | first1 = G. É. | s2cid = 120857543 | doi = 10.1134/1.1355396 | title = Rydberg matter as a metastable state of strongly nonideal plasma | journal = Journal of Experimental and Theoretical Physics Letters | volume = 73 | issue = 1 | pages = 10–12 | year = 2001 |bibcode = 2001JETPL..73...10N }}</ref><ref>{{cite journal | last1 = Manykin | first1 = E. A. | last2 = Zelener | first2 = B. B. | last3 = Zelener | first3 = B. V. | s2cid = 121748296 | doi = 10.1134/S0021364010210125 | title = Thermodynamic and kinetic properties of nonideal Rydberg matter | journal = JETP Letters | volume = 92 | issue = 9 | page = 630 | year = 2011 |bibcode = 2010JETPL..92..630M }}</ref> However, in contrast to electron-hole droplets, Rydberg matter has an extended life-time—as long as hours. This condensed excited [[state of matter]] is supported by experiments, mainly of a group led by Holmlid.<ref>{{cite journal | last1 = Holmlid | first1 = L. | title = Direct observation of circular Rydberg electrons in a Rydberg matter surface layer by electronic circular dichroism | doi = 10.1088/0953-8984/19/27/276206 | journal = Journal of Physics: Condensed Matter | volume = 19 | issue = 27 | page = 276206| year = 2007 |bibcode = 2007JPCM...19A6206H | s2cid = 95032480 }}</ref> It is similar to a liquid or solid state of matter with extremely low (gas-like) density. Lumps of atmospheric Rydberg matter can result from condensation of highly excited atoms that form by atmospheric electrical phenomena, mainly from linear lightning. Stimulated decay of Rydberg matter clouds can, however, take the form of an avalanche, and so appear as an explosion.