Physics
Scientific paper
May 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009agusmsa23a..07m&link_type=abstract
American Geophysical Union, Spring Meeting 2009, abstract #SA23A-07
Physics
2431 Ionosphere/Magnetosphere Interactions (2736), 2463 Plasma Convection (2760), 2483 Wave/Particle Interactions (7867)
Scientific paper
Observations show that transverse heating and resultant outflow of ionospheric plasmas is highly correlated with DC electromagnetic energy flux into the ionosphere. This suggests a mechanism powered by the motion of plasmas through the neutral upper atmosphere, rather than by magnetic field-aligned current flow. The frictional interaction between plasma and gas is closely related to the familiar ion pick up process at heights where the ions are nearly magnetized and dominated by charge exchange interactions with gas. At such heights, a phenomenon called "charge exchange friction" powers velocity space instabilities when the convective drift motion exceeds the neutral thermal speed. The result is a "ring-beam" or toroidal velocity distribution. These have been detected in the ionosphere by direct plasma measurements, inferred from observations of the associated waves, and inferred from the echo spectra of incoherent radar observations of rapidly convecting ionospheric regions. They are unstable to plasma wave growth, and the driven waves must be such as to thermalize the distributions, mainly via perpendicular energy diffusion when ion speeds are much less than the local Alfvén speed. Simple diffusive simulations yield exponential (in v) distributions with power law tails, as observed. The e-folding speed is double the local ion-neutral relative flow speed, as expected for ion pickup. When this process acts along auroral magnetic field lines, the escape flux of ionospheric oxygen increases rapidly with Poynting flux in agreement with observations. Charge exchange friction is a universal plasma process that will produce ion acceleration and heating wherever fast plasma flows are driven through neutral gas.
No associations
LandOfFree
Plasma Heating by Charge Exchange Friction does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Plasma Heating by Charge Exchange Friction, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma Heating by Charge Exchange Friction will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1108493