Journal article
Nightside Pi2Wave Properties During an Extended Period With Stable Plasmapause Location and Variable Geomagnetic Activity
Journal of geophysical research. Space physics, Vol.122(12), pp.12120-12139
12/01/2017
DOI: 10.1002/2017JA024708
Abstract
The frequencies and amplitudes of inner magnetosphere Pi2 waves are affected by the radial plasma density profile. Variable geomagnetic activity and external driving conditions can affect both wave properties and density profiles simultaneously. When interpreting observations, this can lead to ambiguity about whether changing wave properties are due to changing external conditions, density profiles, or a combination of factors. We present a case study using multipoint ground-based and in situ measurements to examine Pi2 wave properties during a period of variable geomagnetic activity. Multiple satellite passes demonstrate the density profile and plasmapause location are stable for at least 2 h over a wide range of magnetic local time. This stability allows us to examine how factors besides the radial density profile affect Pi2 wave properties. We find evidence for Pi2 waves with a broadband frequency spectrum as well as a discrete frequency plasmaspheric virtual resonance (PVR) that is observed at low, middle, and high latitudes and both inside and outside the plasmapause. The PVR is excited in repeated bursts before, during, and after (1) the development of a substorm, (2) several auroral intensifications, (3) the development of Subauroral Polarization Stream flows/electric fields/conductivities, and (4) variable interplanetary magnetic field conditions. Through all these changes the PVR frequency remains remarkably stable (8.2 +/- 0.53 mHz, based on low-latitude ground magnetometer observations), suggesting that these variations have little effect on the frequency. This is consistent with PVR model predictions for a stationary plasmapause.
Details
- Title: Subtitle
- Nightside Pi2Wave Properties During an Extended Period With Stable Plasmapause Location and Variable Geomagnetic Activity
- Creators
- M. D. Hartinger - Virginia TechS. Zou - University of Michigan–Ann ArborK. Takahashi - Johns Hopkins University Applied Physics LaboratoryX. Shi - Virginia TechR. Redmon - National Oceanic and Atmospheric AdministrationJ. Goldstein - Southwest Research InstituteW. Kurth - University of IowaJ. W. Bonnell - University of California, Berkeley
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.122(12), pp.12120-12139
- Publisher
- Amer Geophysical Union
- DOI
- 10.1002/2017JA024708
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 20
- Grant note
- 921647; NAS5-01072 / JHU/APL under NASA national scientific funding agenciy of United States AGS-1342968; AGS-1341918; AGS-1004814 / NSF; National Science Foundation (NSF) national scientific funding agenciy of China national scientific funding agenciy of United Kingdom national scientific funding agenciy of Norway Canadian Space Agency NNX17AD35G; NNX15AI95G; NAS5-02099 / NASA; National Aeronautics & Space Administration (NASA) national scientific funding agenciy of France 1341918 / Directorate For Geosciences; National Science Foundation (NSF); NSF - Directorate for Geosciences (GEO) national scientific funding agenciy of Japan national scientific funding agenciy of Canada national scientific funding agenciy of Italy 922613 / JHU/APL national scientific funding agenciy of Australia national scientific funding agenciy of South Africa
- Language
- English
- Date published
- 12/01/2017
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455549002771
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