CUTLASS Finland radar observations of the ionospheric signatures of flux transfer events and the resulting plasma flows
Reads0
Chats0
TLDR
In this paper, a detailed study of one day of this data revealed a convection reversal boundary in the CUTLASS field of view (f.o.v) on the dayside, the direction of plasma flow either side of the boundary being typical of a dawn-cell convection pattern.Abstract:
. The CUTLASS Finland radar has been run in a two-beam special scan mode, which offered excellent temporal and spatial information on the flows in the high-latitude ionosphere. A detailed study of one day of this data revealed a convection reversal boundary (CRB) in the CUTLASS field of view (f.o.v) on the dayside, the direction of plasma flow either side of the boundary being typical of a dawn-cell convection pattern. Poleward of the CRB a number of pulsed transients are observed, seemingly moving away from the radar. These transients are identified here as the ionospheric signature of flux transfer events (FTEs). Equatorward of the CRB continuous backscatter was observed, believed to be due to the return flow on closed field lines. The two-beam scan offered a new and innovative opportunity to determine the size and velocity of the ionospheric signatures associated with flux transfer events and the related plasma flow pattern. The transient signature was found to have an azimuthal extent of 1900 ± 900 km and an poleward extent of ∼250 km. The motion of the transient features was in a predominantly westward azimuthal direction, at a velocity of 7.5 ± 3 km. Key words. Magnetospheric physics (auroral phenomena; magnetopause · cusp and boundary layers; magnetosphere - ionosphere interaction)read more
Citations
More filters
Journal ArticleDOI
A decade of the Super Dual Auroral Radar Network (SuperDARN): scientific achievements, new techniques and future directions
Gareth Chisham,Mark Lester,Steve Milan,Mervyn P. Freeman,William A. Bristow,Adrian Grocott,Kathryn A. McWilliams,J. M. Ruohoniemi,Tim K. Yeoman,Peter. Dyson,R. A. Greenwald,Takashi Kikuchi,Michael Pinnock,J.P.S. Rash,Noriaki K. Sato,George J. Sofko,Jean-Paul Villain,Anthony Walker +17 more
TL;DR: The Super Dual Auroral Radar Network (SuperDARN) as discussed by the authors has been operating as an international co-operative organization for over 10 years and has been successful in addressing a wide range of scientific questions concerning processes in the magnetosphere, ionosphere, thermosphere, and mesosphere, as well as general plasma physics questions.
Journal ArticleDOI
Variations in the polar cap area during two substorm cycles
Steve Milan,Mark Lester,Stanley W. H. Cowley,Kjellmar Oksavik,Mitchell J. Brittnacher,R. A. Greenwald,George J. Sofko,Jean-Paul Villain +7 more
TL;DR: In this article, the authors employed observations from several sources to determine the location of the polar cap bound-ary, or open/closed field line boundary, at all local times, allowing the amount of open flux in the magnetosphere to be quantified.
Journal ArticleDOI
Convection and auroral response to a southward turning of the IMF : Polar UVI, CUTLASS, and IMAGE signatures of transient magnetic flux transfer at the magnetopause
TL;DR: In this article, the first spacecraft-borne imager observations of the auroral manifestation of transient magnetic flux transfer at the magnetopause were presented, during an interval of interplanetary magnetic field Bz ≈ −10 nT and By ≈ 10 nT, and solar wind dynamic pressure and velocity Psw ≈ 5 nPa and vsw vw ≈ 650 km s−1, Polar Ultraviolet Imager (UVI) images show a sequence of events, each of which begins as a bifurcation of the main auroral oval in
Journal ArticleDOI
Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF radars
Nozomu Nishitani,J. M. Ruohoniemi,Mark Lester,J. B. H. Baker,A. V. Koustov,Simon G. Shepherd,Gareth Chisham,Tomoaki Hori,Evan G. Thomas,Roman A. Makarevich,Aurélie Marchaudon,P. V. Ponomarenko,Jim Wild,Stephen E. Milan,William A. Bristow,John Devlin,Ethan S. Miller,R. A. Greenwald,Tadahiko Ogawa,Takashi Kikuchi +19 more
TL;DR: The Super Dual Auroral Radar Network (SuperDARN) is a network of highfrequency (HF) radars located in the high and mid-latitude regions of both hemispheres that is operated under international cooperation as mentioned in this paper.
Journal ArticleDOI
Space weather challenges of the polar cap ionosphere
TL;DR: In this paper, the SuperDARN convection model is used to track polar cap ionosphere patches backward and forward in time, which can be used to forecast its destination in the future.
References
More filters
Journal ArticleDOI
Interplanetary Magnetic Field and the Auroral Zones
TL;DR: In this article, it was found that a model with a southward interplanetary magnetic field leads to a natural explanation of the SD currents and speculative aspects of the problem as they appear at this time are discussed.
Journal ArticleDOI
The WIND magnetic field investigation
R. P. Lepping,M. H. Acũna,L. F. Burlaga,William M. Farrell,James A. Slavin,K. H. Schatten,F. Mariani,Norman F. Ness,Fritz M. Neubauer,Y. C. Whang,J. B. Byrnes,R. S. Kennon,P. V. Panetta,John Scheifele,E. M. Worley +14 more
TL;DR: The magnetic field experiment on WIND will provide data for studies of a broad range of scales of structures and fluctuation characteristics of the interplanetary magnetic field throughout the mission, and, where appropriate, relate them to the statics and dynamics of the magnetosphere.
Journal ArticleDOI
DARN/SUPERDARN : A global view of the dynamics of high-latitude convection
R. A. Greenwald,K. B. Baker,J. R. Dudeney,Michael Pinnock,T. B. Jones,E. C. Thomas,Jean-Paul Villain,Jean-Claude Cerisier,C. Senior,C. Hanuise,R. D. Hunsucker,George J. Sofko,James A. Koehler,Erling Nielsen,R. J. Pellinen,Anthony Walker,N. Saot,H. Yamagishi +17 more
TL;DR: The Dual Auroral Radar Network (DARN) is a global-scale network of HF and VHF radars capable of sensing backscatter from ionospheric irregularities in the E and F-regions of the high-latitude ionosphere as mentioned in this paper.
Journal ArticleDOI
Initial ISEE Magnetometer Results: Magnetopause Observations (Article published in the special issues: Advances in Magnetospheric Physics with GEOS- 1 and ISEE - 1 and 2.)
C. T. Russell,R. C. Elphic +1 more
Abstract: The magnetic field profiles across the magnetopause obtained by the ISEE-1 and -2 spacecraft separated by only a few hundred kilometers are examined for four passes. During one of these passes the magnetosheath field was northward, during one it was slightly southward, and in two it was strongly southward. The velocity of the magnetopause is found to be highly irregular ranging from 4 to over 40 km s-1 and varying in less time than it takes for a spacecraft to cross the boundary. Thicknesses ranged from 500 to over 1000 km.Clear evidence for reconnection is found in the data when the magnetosheath field is southward. However, this evidence is not in the form of classic rotational discontinuity signatures. Rather, it is in the form of flux transfer events, in which reconnection starts and stops in a matter of minutes or less, resulting in the ripping off of flux tubes from the magnetosphere. Evidence for flux transfer events can be found both in the magnetosheath and the outer magnetosphere due to their alteration of the boundary normal. In particular, their presence at the time of magnetopause crossings invalidates the usual 2-dimensional analysis of magnetopause structure. Not only are these flux transfer events probably the dominant means of reconnection on the magnetopause, but they may also serve as an important source of magnetopause oscillations, and hence of pulsations in the outer magnetosphere. On two days the flux transfer rate was estimated to be of the order of 2 × 1012 Maxwells per second by the flux transfer events detected at ISEE. Events not detectable at ISEE and continued reconnection after passage of an FTE past ISEE could have resulted in an even greater reconnection rate at these times.
Book ChapterDOI
Initial ISEE magnetometer results - Magnetopause observations
TL;DR: The magnetic field profiles across the magnetopause obtained by the ISEE-1 and -2 spacecraft separated by only a few hundred kilometers are examined for four passes as discussed by the authors, during which the magnetosheath field was northward, during one pass it was slightly southward, and in two it was strongly southward.