title: Radio pumping of ionospheric plasma with orbital angular momentum.
abstract: Experimental results are presented of pumping ionospheric plasma with a radio wave carrying orbital angular momentum (OAM), using the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Optical emissions from the pumped plasma turbulence exhibit the characteristic ring-shaped morphology when the pump beam carries OAM. Features of stimulated electromagnetic emissions (SEE) that are attributed to cascading Langmuir turbulence are well developed for a regular beam but are significantly weaker for a ring-shaped OAM beam in which case upper hybrid turbulence dominates the SEE.
authors.affiliation: Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden. thomas.leyser@irfu.se
authors.forename: T B
authors.initials: TB
authors.lastname: Leyser
authors.forename: L
authors.initials: L
authors.lastname: Norin
authors.forename: M
authors.initials: M
authors.lastname: McCarrick
authors.forename: T R
authors.initials: TR
authors.lastname: Pedersen
authors.forename: B
authors.initials: B
authors.lastname: Gustavsson