Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes
In this study we investigate the spectral structure of Pc3–4 pulsations observed at low and midlatitudes. For this purpose, ground-based magnetometer data recorded at the MM100 stations in Europe and at two low latitude stations in South Africa were used. In addition, fluxgate magnetometer data...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-04-01
|
| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/31/725/2013/angeo-31-725-2013.pdf |
| _version_ | 1811282767494774784 |
|---|---|
| author | P. R. Sutcliffe B. Heilig S. Lotz |
| author_facet | P. R. Sutcliffe B. Heilig S. Lotz |
| author_sort | P. R. Sutcliffe |
| collection | DOAJ |
| description | In this study we investigate the spectral structure of Pc3–4 pulsations
observed at low and midlatitudes. For this purpose, ground-based
magnetometer data recorded at the MM100 stations in Europe and at two low
latitude stations in South Africa were used. In addition, fluxgate
magnetometer data from the CHAMP (CHAllenging Minisatellite Payload) low Earth orbit satellite were used. The
results of our analysis suggest that at least three mechanisms contribute to
the spectral content of Pc3–4 pulsations typically observed at these
latitudes. We confirm that a typical Pc3–4 pulsation contains a field line
resonance (FLR) contribution, with latitude dependent frequency, and an
upstream wave (UW) contribution, with frequency proportional to the IMF (interplanetary magnetic field)
magnitude <I>B</I><sub>IMF</sub>. Besides the FLR and UW contributions, the Pc3–4
pulsations consistently contain signals at other frequencies that are
independent of latitude and <I>B</I><sub>IMF</sub>. We suggest that the most likely
explanation for these additional frequency contributions is that they are
fast mode resonances (FMRs) related to cavity, waveguide, or virtual modes.
Although the above contributions to the pulsation spectral structure have
been reported previously, we believe that this is the first time where
evidence is presented showing that they are all present simultaneously in
both ground-based and satellite data. |
| first_indexed | 2024-04-13T01:58:27Z |
| format | Article |
| id | doaj.art-a82bf515e13140f78d9591a310c2f57f |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-04-13T01:58:27Z |
| publishDate | 2013-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-a82bf515e13140f78d9591a310c2f57f2022-12-22T03:07:41ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762013-04-013172574310.5194/angeo-31-725-2013Spectral structure of Pc3–4 pulsations: possible signatures of cavity modesP. R. Sutcliffe0B. Heilig1S. Lotz2South African National Space Agency (SANSA) Space Science, Hermanus, South AfricaTihany Geophysical Observatory, Geological and Geophysical Institute of Hungary, Tihany, HungarySouth African National Space Agency (SANSA) Space Science, Hermanus, South AfricaIn this study we investigate the spectral structure of Pc3–4 pulsations observed at low and midlatitudes. For this purpose, ground-based magnetometer data recorded at the MM100 stations in Europe and at two low latitude stations in South Africa were used. In addition, fluxgate magnetometer data from the CHAMP (CHAllenging Minisatellite Payload) low Earth orbit satellite were used. The results of our analysis suggest that at least three mechanisms contribute to the spectral content of Pc3–4 pulsations typically observed at these latitudes. We confirm that a typical Pc3–4 pulsation contains a field line resonance (FLR) contribution, with latitude dependent frequency, and an upstream wave (UW) contribution, with frequency proportional to the IMF (interplanetary magnetic field) magnitude <I>B</I><sub>IMF</sub>. Besides the FLR and UW contributions, the Pc3–4 pulsations consistently contain signals at other frequencies that are independent of latitude and <I>B</I><sub>IMF</sub>. We suggest that the most likely explanation for these additional frequency contributions is that they are fast mode resonances (FMRs) related to cavity, waveguide, or virtual modes. Although the above contributions to the pulsation spectral structure have been reported previously, we believe that this is the first time where evidence is presented showing that they are all present simultaneously in both ground-based and satellite data.https://www.ann-geophys.net/31/725/2013/angeo-31-725-2013.pdf |
| spellingShingle | P. R. Sutcliffe B. Heilig S. Lotz Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes Annales Geophysicae |
| title | Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes |
| title_full | Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes |
| title_fullStr | Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes |
| title_full_unstemmed | Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes |
| title_short | Spectral structure of Pc3–4 pulsations: possible signatures of cavity modes |
| title_sort | spectral structure of pc3 4 pulsations possible signatures of cavity modes |
| url | https://www.ann-geophys.net/31/725/2013/angeo-31-725-2013.pdf |
| work_keys_str_mv | AT prsutcliffe spectralstructureofpc34pulsationspossiblesignaturesofcavitymodes AT bheilig spectralstructureofpc34pulsationspossiblesignaturesofcavitymodes AT slotz spectralstructureofpc34pulsationspossiblesignaturesofcavitymodes |