Identification

Title

Estimating the azimuthal mode structure of ULF waves based on multiple GOES satellite observations

Abstract

Characterizing the azimuthal mode number, m, of ultralow-frequency (ULF) waves is necessary for calculating radial diffusion of radiation belt electrons. A cross-spectral technique is applied to the compressional Pc5 ULF waves observed by multiple pairs of GOES satellites to estimate the azimuthal mode structure during the 28-31 May 2010 storm. We find that allowing for both positive and negative m is important to achieve a more realistic distribution of mode numbers and to resolve wave propagation direction. During the storm commencement when the solar wind dynamic pressure is high, ULF wave power is found to dominate at low-mode numbers. An interesting change of sign in m occurred around noon, which is consistent with the driving of ULF waves by solar wind buffeting around noon, creating antisunward wave propagation. The low-mode ULF waves are also found to have a less global coverage in magnetic local time than previously assumed. In contrast, during the storm main phase and early recovery phase when the solar wind dynamic pressure is low and the auroral electrojet index is high, wave power is shown to be distributed over all modes from low to high. The high-mode waves are found to cover a wider range of magnetic local time than what was previously assumed. Furthermore, to reduce the 2n pi ambiguity in resolving m, a cross-pair analysis is performed on satellite field measurements for the first time, which is demonstrated to be effective in generating more reliable mode structure of ULF waves during high auroral electrojet periods.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7d79fj7

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

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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

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Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2019-07-30T00:00:00Z

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Conformity

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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