[Report published in Astronomy & Geophysics 40, 3.31-3.33 (June 1999)]
M Grande, M Carter , C H Perry (RAL), Correlation between DST and relativistic electrons during magnetic storms.
Aberystwyth: Department of Physics, University of Wale, Aberystwyth
ACSE: Automatic Control and Systems Engineering, University of Sheffield
Aerospace Corp.: The Aerospace Corporation, USA
BAS: British Antarctic Survey
BGS: British Geological Survey
Birmingha: University of Birmingham
Boston: Boston University, USA
Braunschweig: Technische Universitat von Braunschweig, Braunschweig, Germany
CETP-SM: Centre d'etude des Environnements Terrestre et Planetaires, Saint-Maur, Cedex, France
CETP-UVSQ: Centre d'etude des Environnements Terrestre et Planetaires, Velizy, France
CNRS: Centre National de le Recherche Scientifique, France
Cranfield: University of Cranfield, RMCS Shrivenham
CRL: Communication Research Laboratory, Hiraiso, Japan
Durham: University of Durham
EISCAT: EISCAT Scientific Association
Fairbanks: University of Fairbanks
FMI: Finnish Meteorogical Institute, Finland
Hovemere Ltd: Hovemere Ltd. Keston, Bromley, Kent
IC: Imperial College, London
IKI: Russian Space Research Institute, Moscow
Iowa: University of Iowa, USA
ISAS: Istitute of Space and Astronautical Science, Japan
ISS: ISS, Bucharest, Romania
John Hopkins: Applied Physics Laboratory, The John Hopkins University
Lancaster: Communication Research Centre, University of Lancaster
Leicester : Department of Physics and Astronomy, University of Leicester
Lockheed: Lockheed Martin Palo Alto Res. Lab.
LPCE: Laboratoire de physique et chimie de l'environnement
LSEET: Laboratoire de sondages electromagnetiques de l'enviroment terrestre
MPAe: Max-Planck Institute Fur Aeronomie, Katlenburg-Lindau, Germany
MPE: Max-Planck Institut for Extraterrestrische Physik, Garching, Germany
MSSL: Mullard Space Science Laboratory
Newcastle: University of Newcastle, Australia
Oxford: Atmos. Ocean. and Planetary Physics, Oxford University
QMW: Astronomy Unit, Queen Mary and Westfield College, London
RAL: Rutherford Applenton Laboratory
Sheffield: Upper Atmosphere Group, Dept. of Applied Maths., University of Sheffield
SISP: Swedish Institute of Space Physics, Sweden
Soton: University of Southampton
SSC: Space Science Centre, University of Sussex
St. Andrews: University of St. Andrews
STELab: Solar Terrestrial Environment Lab, University of Nagoya, Japan
UCL: Atmospheric Physics Lab, University College London
UCLA: University of California, Los Angeles, USA
UCLan: University of Central Lancashire
UNIS: University Courses in Svalbard, Longyearbyen, Norway
Uppsala: Uppsala University, Sweden
Warwick: University of Warwick
Washington: University of Washington, USA
York: Magnetospheric Physics Group, Department of Physics, University of York
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by A J Smith (British Antarctic Survey, Cambridge) and C F del-Pozo (University of Lancaster)
Published in Astronomy & Geophysics 40, 3.31-3.33 (June 1999)
The 1999 spring MIST (magnetosphere, ionosphere and solar-terrestrial) meeting, hosted by Lancaster University at Charlotte Mason College, Ambleside, attracted a record 120 participants and 80 papers, necessitating a poster session for the first time. The MIST community clearly continues to thrive. In this report, we can do no more than refer to the individual contributions of this busy meeting, and try to pick out a few the highlights.
To begin the meeting with auroral studies, Betty Lanchester described the small scale dynamics observed in filamentary parallel auroral arcs seen optically and as they passed through the EISCAT field of view. A new 3D non steady state model explained the observed Ohmic heating and density depletions by field aligned currents associated with the arcs. Mike Kosch showed maps of the characteristic energies of precipitating auroral electrons obtained by combining data from the Skibotn digital all-sky imager and the Kilpisjärvi imaging riometer. Anasuya Aruliah described a proposed new scanning Doppler interferometer with a wide field of view to resolve medium-scale structure in neutral winds driven by auroral heating. EISCAT and FPI neutral wind measurements at two altitudes were combined with the Sheffield Coupled Thermosphere Ionosphere Plasmasphere (CTIP) model by Alan Aylward to investigate the contribution of the neutral wind dynamo to high-latitude electrodynamics. The climatology of thermospheric meridional neutral winds could now be obtained from the comparison of long-term EISCAT and FPI databases, reported Eoghan Griffin. Up to 1750 AD, only six auroral events were reported independently from more than one site. David Willis analysed common features in descriptions from Japan, China, Korea and Europe.
The mesosphere/thermosphere session started with four papers from Aberystwyth. Firstly Phil Williams compared the tidal and quasi-tidal oscillations in the lower thermosphere as measured simultaneously by EISCAT at Longyearbyen and Tromsø. Radar observations along the magnetic field line were used to determine the meridional component of neutral wind velocity at a number of heights in the 90-120 km range. Then Vicky Howells discussed the diurnal-, semidiurnal- and planetary-wave-period modulation of gravity-wave activity in the mesosphere and lower thermosphere. The time-series analysis of meteor radar data from Sheffield, between June 1989 and October 1994, revealed strong modulation of the gravity-wave variance at tidal and planetary-wave periods. Helen Middleton discussed the 16-day planetary wave in the mesosphere and lower thermosphere using data from the same meteor radar in 1990-1994 and suggested that the westward phase of the equatorial QBO does not completely prevent inter-hemispheric ducting of the wave from the winter hemisphere, or that it is generated in situ. Next, Dora Pancheva addressed the climatological characteristics of nonlinear coupling between tides and planetary waves using the same data set, particularly between the semidiurnal tide and planetary waves at periods of 2, 4-6, 8-10 and 16 days; the coupling with the diurnal tide is very weak. Matt Harris presented a new general circulation model for the upper mesosphere/ lower thermosphere which extends and updates the existing thermospheric code to incorporate mesospheric dynamics and energetics. Closing this session, David Rees previewed some of the current and future capabilities of ALOMAR in northern Scandinavia for studies of stratospheric and mesospheric / lower thermospheric dynamics and energetics.
The SUPERDARN radars provided the basis for the next three talks which opened the ionosphere sessions. Gaby Provan showed maps of large-scale high-latitude convection derived from spatially averaged radar line-of-sight velocities, supplemented by a statistical model outside the SuperDARN field of view. CUTLASS radar data can be used to derive neutral winds in the upper mesosphere from meteor scatter; Paul Byrne described techniques to remove contamination from other sources of scatter, e.g. sporadic-E. Alan Rodger reported a 4-radar wide-latitude case study of the cusp, identified by the high-spectral width boundary, and its relation to the IMF clock angle. The inverse relation between EISCAT-measured auroral electric fields and absorption seen by IRIS in regions of Farley-Buneman instability was discussed by Carlos del Pozo. Using the Sheffield University Plasmasphere/Ionosphere model Martin Birch explained the application of effective height corrections to oblique total content measurements obtained from GPS satellite transmissions. Richard Balthazor had used the Sheffield CTIP model to look at the response of the daytime mid-latitude ionospheric trough to intense activity bursts. Good agreement with ionospheric tomography measurements was found. A new type of D-region plasma instability, the Electron Pedersen Conductivity Instability, and its radar signature, was reported by Ranvir Dhillon.
Continuing with the ionosphere in the next session, Ian Walker presented two case studies of measurements of red-line auroral emissions and electron density structures imaged by radio tomography associated with dayside precipitation and the possible formation of polar-cap patches. Yuanchi Su discussed the equinoctial asymmetry in the low-latitude topside ionosphere using observations from the Hinotori satellite, and the CTIP model. Adam Smith addressed the high-latitude ionospheric response to changes in IMF clock angle using WIND satellite data, optical measurements by the meridian scanning photometer at Ny-Ålesund, and the CUTLASS Finland HF radar. Gareth Chisham discussed high-time resolution observations from the SuperDARN radars of the response of dayside convection to changes in IMF. Data from radars in both hemispheres and from a number of satellites were used. Tim Yeoman presented a statistical study of the occurrence rates and repetition frequencies of pulsed ionospheric flows in the dayside auroral zone as detected by CUTLASS Finland.
To finish the session two papers described the risk of strong geomagnetically induced currents (GICs) on the ground, in the UK. The first, given by Ellen Clarke, discussed the effects of magnetic variations and a simple measure of their strength to be used to determine the GIC risk according to season and local time. The second paper by Alan Thomson described a 3-D geology model to estimate the surface electric field in the UK for various amplitudes and wavelengths of the external magnetic field variation. In particular, very strong E-fields may be produced around the coast by the high conductivity contrast between seawater and the on-shore geology.
The two magnetospheric sessions began with an analysis of SAR arcs and diffuse aurora, seen at sub-auroral Millstone Hill by Michael Mendillo, which implied the nighttime colocation of the plasmasheet boundary and the plasmapause, and a proton precipitation contribution to SAR arcs. Mick Denton reported how inclusion of an improved thermal conductivity into the Sheffield plasmasphere ionosphere model produced electron temperatures in better agreement with observation. Raphael André reported how coherent radar spectral widths arising from multi-component autocorrelation functions were associated with microscopic plasma turbulence and time-varying electric fields. Moving now to the cusp, Ian Krauklis explained how O+ and H+ bulk velocity and temperature data, obtained in 10 Polar/TIMAS crossings, were consistent with acceleration and heating by wave-particle interactions. John Storey presented a case study of the growth and expansion phases of a substorm in terms of plasma sheet boundary crossings, magnetic field configurations, and auroral UV images observed by the Polar satellite. Finally in this session Andy Smith described the use of data from Halley, Antarctica, to quantify the VLF radio wave energy from lightning present in the magnetosphere in the form of ducted whistler mode waves.
In the second session on magnetospheric physics, Manuel Grande examined the relationship between variations in Dst and the relativistic electron flux during magnetic storms using data from the CRRES and LANL satellites. Negative excursions in Dst during all phases of major storms are accompanied by significant reductions in the flux of radiation belt electrons while increases in Dst correspond to increases in the electron flux. Katie Mills presented a model for the coupling of unstable fast cavity modes to field line resonances (FLRs) and showed that the predicted azimuthal phase speeds are in good agreement with observations. Ian Mann discussed the possibility of diagnosing the excitation mechanisms of Pc5 waves and suggested that the characteristics of multiple harmonic FLRs, driven by waveguide modes, can be used to diagnose their energy sources. Using Pc5 observations from the IMAGE magnetometer array, Rod Mathie showed that mHz FLRs represent local enhancements in the background Alfvén continuum of field line eigenfrequencies. Closing this session, Tim Woodward discussed the structure of the magnetosheath just upstream of the magnetopause using data from the dual spacecraft AMPTE IRM/UKS mission.
In order to accommodate the large number of contributions to this MIST meeting, a poster session displaying 14 papers was included in the programme. This poster session was preceded by a series of brief previews given by the authors.
Phil Williams began with a paper comparing phase velocities measured by the STARE radar and predictions using simultaneous EISCAT observations inside and outside the instability cone during the 1988 ERRIS campaign. Ingo Mueller-Wodarg presented a study of the thermospheric meridional circulation and its effect on composition by applying the CTIP model, and David Rees followed with a brief overview of recent observations of momentum coupling in the high latitude thermosphere and ionosphere and ionosphere by Doppler imaging systems. Mark Clilverd mentioned his poster on seismo-ionospheric effects on a long subionospheric path, Jim Wild previewed multi-instrument observations of omega-bands and their associated magnetic signatures, and Iain Coleman addressed the ionospheric footprint of the magnetopause merging line as predicted by the anti-parallel merging hypothesis.
Four posters with main authors from Leicester were introduced, one by Jackie Davies on the EISCAT UHF observations during an F-region ionospheric modification experiment from the October 1998 UK Campaign, another by Steve Milan on magnetospheric convection and auroral response to a southward turning of the IMF and the possibility of POLAR UVI, CUTLASS and IMAGE signatures of flux transfer events, a third one by Tim Yeoman on the sunward convection and global magnetospheric oscillations driven by lobe reconnection during an extended period of northward IMF, and a fourth by Dave Neudegg giving a survey of magnetopause FTEs and associated flow bursts in the polar ionosphere.
Simon Walker introduced his poster on the spatial sizes of electric and magnetic field gradients in a simulated shock; this was followed by two related papers on the modelling of Jupiter's auroral electrojet by Nicholas Achilleos and on the H3+ spectroscopy of the Jovian aurora by Tom Stallard. The session ended with a preview by Gareth Lawrence of the Atmospheric X-Ray Observatory mission.
The common theme of the next five talks from Sheffield, which introduced the solar wind/ magnetosheath session, was nonlinear processes particularly in the magnetosheath region. Misha Balikhin began by explaining nonlinear process identification and the generalisation of the transfer function to 3-wave and higher processes. This was applied to spaced AMPTE UKS and IRM observation of MIAOW (Mirror and Slow mode waves). Meanwhile Interball data upstream of a quasi-perpendicular shock had been analysed by Simon Walker to infer that whistler mode turbulence results from 3-wave interaction decay of a low frequency nonlinear wave. Ian Bates applied the same concept, this time to AMPTE UKS and IRM data just downstream of the bow shock, deducing the existence of instability regions just inside the magnetosheath. Daniel Coca introduced the NARMAX method for analysing nonlinear system as a "grey box" and applied it to SLAMS, short large-amplitude waves upstream of the shock; he found good agreement between observation and theory. Otilia Boaghe also used NARMAX, this time applying it to the whole magnetosphere, with the solar wind and the Dst index considered as input and output functions, respectively. A simple 1D MHD model of the high altitude cusp, in which plasma flows supersonically into a triangular well by the Prandt-Meyer effect, was presented by Matt Taylor. Rosalind Mist modelled velocity distributions in the tail lobes just inside the magnetopause, resulting from high-latitude reconnection, and compared with the double ion beams seen by Geotail. Wave-particle interactions are important in maintaining charge neutrality in the ion velocity filter region of the cusp, according to Steve Topliss who had analysed data from the TIMAS and HYDRA instruments on Polar.
The spacecraft observations session started with a report by Andy Fazakerley on the current status of the Cluster II mission, due for launch in mid-2000. The talk highlighted the changes from Cluster I and discussed the expected nature of conjunctions with the Svalbard radar. Then Andy Buckley presented an outline of the Cluster II particle correlator and discussed the simulations of wave-particle interaction measurements to be made by Cluster.
Calculations of electron pitch angle diffusion by electrostatic electron cyclotron harmonic waves were presented by Richard Horne to demonstrate that diffusion caused by the growth of ECH cannot be responsible for the formation of highly anisotropic pancake distributions near the magnetic equator outside the plasmapause. Nigel Meredith discussed the temporal evolution of injected electron distributions in the inner magnetosphere using data from the CRRES satellite, and showed that pancake electron distributions are seen to develop from injected distributions that are nearly isotropic in velocity space. Elizabeth Lucek reported on the magnetic field signatures observed by the Equator-S satellite in the dawn-side magnetosheath. Analysis of these signatures indicated that they occur under conditions when the field has a draped configuration, and that the fluctuations lie in a plane parallel to the observed magnetopause boundary. Gary Abel discussed the acceleration of field aligned electrons observed by the LEPA instrument on the CRRES satellite and showed that counter streaming beams of electrons do not follow the theoretical diffusion curves for the resonant interaction between electrons and whistler modes. The session concluded with the paper by Jonny Rae presenting the statistical study of pulsed particle signatures in the cusp region as observed by the Polar satellite.
The last afternoon was occupied by a special planetary session, arranged by Dave Hawksett of the UK Planetary forum (http://ast.star.rl.ac.uk/forum/) . Topics ranged from the solar corona, to Mars, Jupiter and Saturn.
Henry Rishbeth drew the meeting to a close by thanking all who had contributed, and especially Farideh Honary, the local organiser.