imported>Perlwikibot |
|
| Line 1: |
Line 1: |
| | | #REDIRECT: [[Small ion]] |
| #REDIRECT [[small ion]] | |
| | |
| {{TermHeader}}
| |
| {{TermSearch}}
| |
| | |
| <div class="termentry">
| |
| <div class="term">
| |
| == small ion ==
| |
| </div>
| |
| | |
| <div class="definition"><div class="short_definition">(''Also called'' light ion, fast ion.) An atmospheric [[ion]] of the type that has the greatest [[mobility]] and hence, collectively, is the principal agent of atmospheric [[conduction]].</div><br/> <div class="paragraph">The exact physical nature of the small ion has never been fully clarified, but much evidence indicates that each is a singly charged atmospheric molecule (or, rarely, an atom) about which a few other neutral molecules are held by the electrical attraction of the central ionized molecule. Estimates of the number of satellite molecules are as high as twelve. When freshly formed by any of several [[atmospheric ionization]] processes, small ions are probably singly charged molecules, but after a number of collisions with neutral molecules they acquire (actually, in a fraction of a second) their cluster of satellites. Even with these satellites clustering about the central charged molecules, the [[ion mobility]] of the resulting complex is of the order of 10<sup>4</sup> times greater than that of large ions. Negative small ions exhibit slightly greater mobilities than positive small ions, 1.9×10<sup>-4</sup> m s<sup>-1</sup> per volt cm<sup>-1</sup> being typical of negative, and 1.4×10<sup>-4</sup> m s<sup>-1</sup> per volt m<sup>-1</sup> being typical of positive small ions in [[dry air]] at [[sea level]]. Small ions may disappear either by direct [[recombination]] with oppositely charged small ions or by combination with neutral [[Aitken nuclei]] to form new [[large ions]], or by combination with large ions of opposite sign. The concentration of small ions near sea level is typically about 5×10<sup>-4</sup> of each sign per m<sup>3</sup>, both over the oceans and over land. This concentration increases with [[altitude]], and at 18 km it is about 10<sup>-3</sup> per m<sup>3</sup>.</div><br/> </div>
| |
| </div>
| |
| | |
| {{TermIndex}}
| |
| {{TermFooter}}
| |
| | |
| [[Category:Terms_S]]
| |
