Numerical study of upper hybrid to Z-mode leakage during electromagnetic pumping of groups of striations in the ionosphere
2015 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 33, no 8, 1019-1030 p.Article in journal (Refereed) Published
We investigate numerically the interaction between ionospheric magnetic field-aligned density striations and a left-hand circularly polarized (L)-mode wave. The L-mode wave is scattered into upper hybrid (UH) waves which are partially trapped in the striations, but leak energy to electromagnetic waves in the Z-mode branch. For small-amplitude (1 %) striations, this loss mechanism leads to a significant reduction in amplitude of the UH waves. For several striations organized in a lattice, the leaking of Z-mode waves is compensated by influx of Z-mode radiation from neighboring striations, leading to an increased amplitude of the weakly trapped UH waves. For large-amplitude (10 %) striations the trapped UH waves rapidly increase in amplitude far beyond the threshold for parametric instabilities, and the Z-mode leakage is less important. The results have relevance for the growth of striations and the onset of UH and lower hybrid turbulence during electromagnetic high-frequency pumping of ionospheric plasma, which require large-amplitude UH waves.
Place, publisher, year, edition, pages
2015. Vol. 33, no 8, 1019-1030 p.
Ionosphere (active experiments, ionospheric irregularities, wave propagation)
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:uu:diva-264337DOI: 10.5194/angeo-33-1019-2015ISI: 000360651100009OAI: oai:DiVA.org:uu-264337DiVA: diva2:860886