Pulsed Flows at the High-Altitude Cusp Poleward Boundary, and Associated Ionospheric Convection and Particle Signatures, During a Cluster/FAST/SuperDARN/Sondrestrom Conjunction <p> HR: <span class="hr"> 11:35h<br></span> AN: <span class="an"> SH51B-06 <a href="../absbook/fm03-SH51B.pdf">[PDF]</a><br></span> TI: <span class="ti"> Pulsed Flows at the High-Altitude Cusp Poleward Boundary, and Associated Ionospheric Convection and Particle Signatures, During a Cluster/FAST/SuperDARN/Sondrestrom Conjunction Under a Southwest IMF<br></span> AU: <span class="au"> * Farrugia, C J<br></span> EM: <span class="em"> charlie.farrugia@unh.edu<br></span> AF: <span class="af"> Space Science Center, University of New Hampshire, Durham, NH 03824 United States<br></span> AU: <span class="au"> Lund, E J<br></span> EM: <span class="em"> eric.lund@unh.edu<br></span> AF: <span class="af"> Space Science Center, University of New Hampshire, Durham, NH 03824 United States<br></span> AU: <span class="au"> Sandholt, P <br></span> EM: <span class="em"> p.e.sandholt@fys.uio.no<br></span> AF: <span class="af"> Department of Physics, University of Oslo, Oslo, N-0316 Norway <br></span> AU: <span class="au"> Wild, J <br></span> EM: <span class="em"> J.Wild@ion.le.ac.uk<br></span> AF: <span class="af"> Radio and Space Plasma Group, University of Leicester, Leicester, LE1 7RH United Kingdom <br></span> AU: <span class="au"> Cowley, S W<br></span> EM: <span class="em"> swhc1@ion.le.ac.uk<br></span> AF: <span class="af"> Radio and Space Plasma Group, University of Leicester, Leicester, LE1 7RH United Kingdom <br></span> AU: <span class="au"> Balogh, A <br></span> EM: <span class="em"> a.balogh@ic.ac.uk<br></span> AF: <span class="af"> Blackett Laboratory, Imperial College, London, SW7 2Bz United Kingdom <br></span> AU: <span class="au"> Mouikis, C <br></span> EM: <span class="em"> C.mouikis@unh.edu<br></span> AF: <span class="af"> Space Science Center, University of New Hampshire, Durham, NH 03824 United States<br></span> AU: <span class="au"> Mouikis, C <br></span> EM: <span class="em"> C.mouikis@unh.edu<br></span> AF: <span class="af"> Blackett Laboratory, Imperial College, London, SW7 2Bz United Kingdom <br></span> AU: <span class="au"> Moebius, E <br></span> EM: <span class="em"> eberhard.moebius@unh.edu<br></span> AF: <span class="af"> Space Science Center, University of New Hampshire, Durham, NH 03824 United States<br></span> AU: <span class="au"> Dunlop, M <br></span> EM: <span class="em"> M.W.Dunlop@rl.ac.uk<br></span> AF: <span class="af"> Rutherford-Appleton Laboratory, Didcot, Oxford, OX10 United Kingdom <br></span> AU: <span class="au"> Bosqued, J <br></span> EM: <span class="em"> Jean-Michel.Bosqued@cesr.fr<br></span> AF: <span class="af"> Centre d'Etude des Rayonnements Spatiales, Toulouse, Toulouse, 31029 France <br></span> AU: <span class="au"> Carlson, C W<br></span> EM: <span class="em"> cwc@ssl.berkeley.edu<br></span> AF: <span class="af"> Space Sciences Laboratories, University of California, Berkeley, Ca United States<br></span> AU: <span class="au"> Parks, G <br></span> EM: <span class="em"> cwc@ssl.berkeley.edu<br></span> AF: <span class="af"> Space Sciences Laboratories, University of California, Berkeley, Ca United States<br></span> AU: <span class="au"> Cerisier, J <br></span> EM: <span class="em"> jean-claude.cerisier@cetp.ipsl.fr<br></span> AF: <span class="af"> CETP, St-Maur, St-Maur, 94107 France <br></span> AU: <span class="au"> Kelly, J D<br></span> EM: <span class="em"> kelly@sri.com<br></span> AF: <span class="af"> SRI International, Menlo Park, Menlo Park, CA United States<br></span> AU: <span class="au"> Sauvaud, J <br></span> EM: <span class="em"> Jean-Andre.Sauvaud@cesr.fr<br></span> AF: <span class="af"> Centre d'Etude des Rayonnements Spatiales, Toulouse, Toulouse, 31029 France <br></span> AU: <span class="au"> Reme, H <br></span> EM: <span class="em"> henri.reme@cesr.fr<br></span> AF: <span class="af"> Centre d'Etude des Rayonnements Spatiales, Toulouse, Toulouse, 31029 France <br></span> AB: <span class="ab"> Observations during a magnetic conjunction Cluster 1-FAST-Sondrestrom within the field of view of SuperDARN radars on January 21, 2001 allow us to draw a comprehensive and self-consistent picture at three heights of signatures of transient reconnection under a steady south-westerly IMF. Cluster 1 was outbound through the high altitude exterior northern cusp when a solar wind dynamic pressure release shifted the spacecraft into a boundary layer at the cusp's poleward edge. Centerpiece of the investigation is a series of flow bursts observed there by the spacecraft, which were accompanied by strong field perturbations and tailward flow deflections, shown to be Alfven waves. We interpret these flow events as being due to a sequence of reconnected flux tubes, with field-aligned currents in the associated Alfven waves carrying stresses to the underlying ionosphere, a view strengthened by the other observations. At the magnetic footprint of the region of Cluster flow bursts, FAST observed an ion energy-latitude disperison of the stepped cusp type, with individual cusp ion steps corresponding to individual flow bursts. Simultaneously, the SuperDARN radars observed very strong PMRAFs which were conjugate to the flow bursts at Cluster. FAST was traversing these PMRAFs when it observed the cusp ion steps. The Sondrestrom radar observed PIFs just poleward of the convection reversal boundary. As at Cluster, the flow was tailward, implying a coherent tailward motion of the hypothesized open flux tubes. The joint Sondrestrom and FAST observations indicate that the open/closed field line boundary was equatorward of the convection reversal boundary by $\sim$2$^{\circ}$. The unprecedented accuracy of the conjunction leaves no doubt as to the validity of the interpretation of the various signatures as resulting from transient reconnection. In particular, the cusp ion steps arise indubitably on this pass from this origin, in consonance with the original pulsating cusp model. The observations argue in favor of re-establishing the poleward boundary of the cusp as an active site of momentum transfer. <br></span> DE: <span class="de"> 2409 Current systems (2708)<br></span> DE: <span class="de"> 2431 Ionosphere/magnetosphere interactions (2736)<br></span> DE: <span class="de"> 2724 Magnetopause, cusp, and boundary layers<br></span> DE: <span class="de"> 2736 Magnetosphere/ionosphere interactions<br></span> DE: <span class="de"> 2784 Solar wind/magnetosphere interactions<br></span> SC: <span class="sc"> SPA - Solar and Heliospheric Physics [SH]<br></span> MN: <span class="mn"> 2003 Fall Meeting<br></span></p></body></html>