Radio pumping of ionospheric plasma with orbital angular momentum.
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.
Leyser
T B
TB
Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden. thomas.leyser@irfu.se
Norin
L
L
McCarrick
M
M
Pedersen
T R
TR
Gustavsson
B
B