Zobrazeno 1 - 10
of 41
pro vyhledávání: '"Hanna Dahlgren"'
Publikováno v:
South African Journal of Science, Vol 107, Iss 9/10 (2011)
A narrowband receiver was installed at the SANAE IV base in Antarctica to monitor specific very low frequency (VLF) radio signals from transmitters around the world. VLF waves propagating through the Earth-Ionosphere Waveguide are excellent probes of
Externí odkaz:
https://doaj.org/article/7d34d38c722445fea78cf3b18bcea4d0
Autor:
Daniel K. Whiter, Hanna Dahlgren, Betty S. Lanchester, Joshua Dreyer, Noora Partamies, Nickolay Ivchenko, Marco Zaccaria Di Fraia, Rosie Oliver, Amanda Serpell-Stevens, Tiffany Shaw-Diaz, Thomas Braunersreuther
Fragmented Aurora-like Emissions (FAEs) are small (few km) optical structures which have been observed close to the poleward boundary of the aurora from the high-latitude location of Svalbard (magnetic latitude 75.3 ° N). The FAEs are only visible i
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::adae8abe05eb3a1d568edb3eebcb9633
https://doi.org/10.5194/angeo-2020-95
https://doi.org/10.5194/angeo-2020-95
Publikováno v:
Journal of Geophysical Research: Space Physics. 121:5966-5974
Technological advances leading to improved sensitivity of optical detectors have revealed that aurora contains a richness of dynamic and thin filamentary structures, but the source of the structured emissions is not fully understood. In addition, hig
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::7bd13690245d4a22e092d563f47e36e3
https://doi.org/10.1002/2016ja022446
https://doi.org/10.1002/2016ja022446
Autor:
Torbjörn Sundberg, Kazuo Shiokawa, Hanna Dahlgren, Steven Chen, Michael J. Nicolls, Keisuke Hosokawa, Gareth Perry, M. Zettergren, Joshua Semeter, J.-P. St.-Maurice
Publikováno v:
Journal of Geophysical Research: Space Physics. 120:9977-9987
Common volume measurements by the Resolute Bay Incoherent Scatter Radar - North (RISR-N) and Optical Mesosphere and Thermosphere Imagers (OMTI) have been used to clarify the electrodynamic structure of a sun-aligned arc in the polar cap. The plasma p
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::6d9f200bfe1beaaf7d9b95229a90892d
https://doi.org/10.1002/2015ja021790
https://doi.org/10.1002/2015ja021790
Publikováno v:
Geophysical Research Letters. 42:1290-1296
High resolution multi-monochromatic measurements of auroral emissions have revealed the first optical evidence of coexisting small-scale auroral features resulting from separate high and low energy populations of precipitating electrons on the same f
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::22938a9cd95624f52f86f18bc373d23a
https://doi.org/10.1002/2015gl063173
https://doi.org/10.1002/2015gl063173
Autor:
Robert A. Marshall, John Noto, Jeffrey Baumgardner, Hanna Dahlgren, Chhavi Goenka, Juanita Riccobono, Michael Migliozzi, Joshua Semeter
Publikováno v:
Advances in Space Research. 52:1366-1377
Multispectral imaging of optical emissions in the Earth’s upper atmosphere unravels vital information about dynamic phenomena in the Earth-space environment. Wavelength tunable filters allow us to accomplish this without using filter wheels or mult
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e852e460a6787ec5ba857ea9c22a95f5
https://doi.org/10.1016/j.asr.2013.06.014
https://doi.org/10.1016/j.asr.2013.06.014
Publikováno v:
Journal of Geophysical Research: Space Physics. 118:4572-4582
[1] High-resolution optical observations of a substorm expansion show dynamic auroral rays with surges of luminosity traveling up the magnetic field lines. Observed in ground-based imagers, this phenomenon has been termed auroral flames, whereas the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::07435e1d2a5219ff1c7d6f39bb15377e
https://doi.org/10.1002/jgra.50415
https://doi.org/10.1002/jgra.50415
Autor:
Hanna Dahlgren, Tima Sergienko, Ingrid Sandahl, Nickolay Ivchenko, Betty Lanchester, Daniel Whiter, Göran Marklund, Urban Brandstrom, Björn Gustavsson
Publikováno v:
Annales Geophysicae, Vol 29, Pp 1699-1712 (2011)
Two discrete auroral arc filaments, with widths of less than 1 km, have been analysed using multi-station, multi-monochromatic optical observations from small and medium field-of-view imagers and the EISCAT radar. The energy and flux of the precipita
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7954251c50161c0d0efb5dd5d28c81ef
https://www.ann-geophys.net/29/1699/2011/angeo-29-1699-2011.pdf
https://www.ann-geophys.net/29/1699/2011/angeo-29-1699-2011.pdf
Publikováno v:
International Journal of Remote Sensing. 32:2973-2985
High-resolution, multi-spectral data from the ground-based low-light auroral imager ASK (Auroral Structure and Kinetics) are used to characterize the fine structure of black aurora. Sixteen events comprising sheared and unsheared black arcs, as well
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9c5cacfe5e6256193010addd846d7ec4
https://doi.org/10.1080/01431161.2010.541517
https://doi.org/10.1080/01431161.2010.541517
Publikováno v:
Annales Geophysicae, Vol 28, Pp 1961-1979 (2010)
Many pulsating phenomena are associated with the auroral substorm. It has been considered that some of these phenomena involve kilometer-scale Alfvén waves coupling the magnetosphere and ionosphere. Electric field oscillations at the altitude of the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5ede3c678eff8fc69b65567335ce8dc2
https://www.ann-geophys.net/28/1961/2010/angeo-28-1961-2010.pdf
https://www.ann-geophys.net/28/1961/2010/angeo-28-1961-2010.pdf