Identification

Title

Electromagnetic waves generated by ionospheric feedback instability

Abstract

A new interactive M-I coupling model that describes the dynamic interaction between magnetospheric dispersive waves, compressional modes, and auroral electron precipitations is applied to investigate the geomagnetic electromagnetic pulsations observed in Earth's magnetosphere in terms of magnetospheric waves triggered by ionospheric feedback instability. Two new aspects of this work are that (1) we treat the full nonlinear MHD equations, i.e., include the full compressional modes and their coupling with shear Alfvén waves in the magnetosphere; and (2) the height-integrated Pedersen conductivity is treated as a dynamic parameter by electrodynamically coupling the 2D finite element wave model "TOPO" to the ionospheric ionization model "GLOW". It is shown that the feedback instability can be triggered by a very small-scale, small amplitude density perturbation; and the small-scale electromagnetic oscillations and their associated density fluctuations observed in magnetosphere can be attributed to the feedback instability. We demonstrate that, unlike in a field line resonance where the ponderomotive force causes the plasma to move mainly along the field line, the plasma in the feedback instability is distributed either as a bump or a cavity along a field line and leads to a multibanded structure in the radial direction. The nonlinear feedback instability model can successfully explain the formation of plasma density and electromagnetic perturbations with the same frequency, which disagree with current FLR scenario.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7qf8t3f

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2008-05-06T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact