---------------------------------------------------------------- REPORT ON 1994 SNOWMASS WORKSHOP - MAGNETOTAIL/SUBSTORM CAMPAIGN ---------------------------------------------------------------- WG 1: Substorm Onset Signatures: Identification, Location, and Timing Co-chairs: Nelson Maynard and Larry Lyons Working Group 1 concentrated on coordinated data-driven studies of substorms with the focus on the spatial/temporal relationships between phenomena. We will explore the timing of phenomena observed in diverse places to better define the phenomenology assoicated with pre-onset, onset and the development of the substorm. Three periods were selected with multip[le substorms in each period: (1) Jan 11-14, 1994, (2) Mar 18- 26, 1993, and (3) Jan., Mar., and Aug., 1991. Period 1 involves coordinated measurements between instrumentation on the ground, in polar orbit, at geosynchronous orbit, and at the Geotail spacecraft at 100 Re in the tail. Period 2 involves data from ground, polat orbitting satellites, geosynchronous orbit, and some Geotail data at 190 Re. Period 3 involves a selected group of substorms with CRRES data available as well as ground, polar orbiting and geosynchronous data. The campaign coordinator for period 1 is Nelson Maynard, for Period 2 - Larry Lyons, and for Period 3 - Jeff Hughes. It was agreed that interpreted data for each of the selected substorms would be sent to the campaign coordinators by 20 October in the case of Periods 1 and 2, and by 15 November in the case of Period 3. Each of the coordinators will attempt to develop a time line based on the interpretations given for each data set for presentation at the mini workshop preceeding the San Francisco AGU this fall. With these roadmaps, next summer's workshop can be devoted to determining what physics can be learned from these studies, The following approximate substorm onsets were identified and the intervals over which data should be plotted are given: Period 1. (Maynard) 11 Jan 1994 0636UT 0530-0730 12 Jan 1994 0450 0350-0550 13 Jan 1994 0100 0000-0200 13 Jan 1994 0315 0215-0415 14 Jan 1994 0630 0530-0730 additional active intervals of possible interst 14 Jan 1994 20-24 hrs (20-22; 22-24) 14 Jan 1994 1730-1830 (16-18; 18-20) Possible contributors: Nakamura Geotail Jaquey Geotail Thomson LANL Geosync Singer GOES Intermagnet Baker SAMPEX Maynard /Denig DMSP Samson/Lyons CANOPUS Friis-Christensen/Lyons Greenland Greenwald Super DARN Foster Millstone Doe Sondestrom Resolute Jacobsen Svalbard Smith Svalbard and Alaska Hughes MACCS Rosenberg South Pole Fraser Pi-2 Period 2 (Lyons) 18 Mar 1993 0015 2330(17th)-0130 20 Mar 1993 0234 0130-0330 0400 0330-0530 21 Mar 1993 00-06 (multiple) 00-02;02-04;04-06 24 Mar 1993 0225 0200-0400 25 Mar 1993 0530 0430-0630 Possible contributors Lyons/Samson CANOPUS Pinnock Goose/Halley Doe Sonde radar Blanchard Sonde optics Stauning Sonde riometer Lyons/Friis-Christensen Greenland Hughes MACCS Smith Alaska Rosenberg South Pole Thomson LANL Geoysnc Singer GOES Lyons/Rich/Blanchard DMSP Nakamura Geotail Fairfield Geotail Angelopoulos Geotail Fraser Antartic Period 3 (Hughes) 24 Jan 1991 0810 0700-0900 9 Mar 1991 0200 0100-0300 0600 0500-0700 23 Mar 1991 0235 0130-0330 2 Aug 1991 0600 0500-0700 Possible contributors Hughes CRRES Maynard CRRES Singer CRRES GOES Lyons/Samson CANOPUS Lyons/ Friis-Christenson Greenland Thomson LANL Geoysync Doe Sondestrom Rosenberg South Pole Others with possible contributory data for any of the periods should contact the campaign coordinator. In addition, two special periods were noted were correlative data is requested by the principals. The first is 20-21 Mar 1990 which has had an extensive AMIE analysis by Delores Knipp. She is looking for correlative satellite and optical data. The second is 1 Mar 1985. Ted Speiser is doing a AMPTE substorm timing study on the substorm at 0242 UT and is looking for correlative data. Two tutorials were sponsored by this working group. Sandy Murphree presented a comprehensive review of the evolution of a substorm based on Viking images. Howard Singer reviewed substorm signatures from the prespective of magnetometer measurements, both ground-based and satellite-borne. Further notes on the selected events based on workshop discussions: JAN. 11-14, 1994: Coordination with GEOTAIL, Greenland, CANOPUS, and Alaska ground data available. Meaningful IMF data only on 1/14 1. 1/11: Isolated onset 0636 UT @ CANOPUS; see pos. Bx at Resolute, pos. By at Igloolik; GEOTAIL in and out of sheath around onset? 2. 1/12: Onset 0450 UT @ Greenland and CANOPUS, MACCS onset 0503 at 74 degrees lat., Cape Dorset, Coral Harbour onset ~0505; Igloolik, Pelly Bay onset ~0540; GEOTAIL strong tailward flow with variable B's 0455 - 0515, in lobes before and after. May be able to get S. hem. mag. data from B. Fraser & T. Rosenberg. 3. 1/13: Substorms 01-0230 (last onset ~0220), 0335 @ Greenland; isolated onset 0315 @ CANOPUS, MACCS; ~0110, ~0320 Cape Dorset, Coral Harbour, Igloolik, Pelly Bay; GEOTAIL strong tailward flow with variable B's 0047 - 0103, 0112 - 0142, 0322 - 0342, earthward flow 0222 - -0232, in lobes before and after flow events. 4. 1/14: Onset 0630 (CANOPUS), ~0650 (Greenland), 0629 MACCS; GEOTAIL earthward flow 0600 - 0637, tailward flow 0637 - 0700, Also onset @ 0300 UT at CANOPUS, 0310 Cape Dorset, Coral Harbour, Igloolik; Pelly Bay (Not seen in Greenland); IMF Bz north. turning at 0253; GEOTAIL mostly earthward flows 0305 - 0327, tailward flow 0327 - 0405 MAR. 18-26, 1993: High-quality optical from Green., CAN., and Alaska 3/18: Onset 0015 (sharp @ Greenland, seen at CANOPUS), no IMF, Good Sondre. optical & imaging riometer, MACCS (sees onset at all 3 stations), S. Pole, and geosynch. data available, nothing from Goose or Halley Bays 3/20: Well defined onsets 0234, 0400 (Greenland) (IMF data gap, but GEOTAIL in sheath), 0400 onset seen at Pang. & Cape Dorset, very small at Repulse Bay, CANOPUS onset 0452. Should be good B data from Iceland, S. Pole 3/21 activity 00-02, 0330-06, (Greenland); onsets ~0508, 0532, 0547 (CANOPUS); IMF available until 0510 (Highly varying Bz); excellent Goose and Halley data; Study interval 00-06 UT; 3/24 nice Greenland onset, CANOPUS pos. bay, 0225; Good S. pole, MACCS (clear onset all 3 stations), Halley data, some Goose Bay, Good Sondre. optical, action at GEOTAIL 0225 3/25 nice isolated onset (750 nT substorm) 0520 (Gillam), 0600 (F. Smith) (1470 km/2400 s = 610 m/s; surge or 2 onsets?) Small DB Green. ~0530; Good Goose and Halley data; Good IMP center-tail B data with lobe Bz sign changes + to - @ ~0515, - to + @ ~ 0543; synch. sat. with energetic particles at right LT. CRRES ONSETS 1. 1/24, 1991: Onset @ 0810 UT, 0013 MLT, L = 7.0, Mag. lat. 15.0; nice isolated CANOPUS onset @ 0805, Slow decrease in neg. IMF Bz begins ~0750 (IMP at x ~ 0, y ~ -35 Re); Very good geosynch. and ground timing info. 2. 3/9 1991: Onset @ 0200 UT, L = 5, sharp north. IMF Bz turning 0150 UT (x = 15, y = 27), see at CANOPUS ~0240 (another north. IMF Bz turning? Separate substorm?) Need Greenland Mag. data; Onset 0600 UT, 2251 MLT, L = 6.7, M. lat. 3.3; see in CANOPUS photom. 0608, need to check mag., no IMF. 3. 3/23, 1991: Onset @ 0235 UT, 2105 MLT, L = 6.4, Mag. lat. 6.7; No IMF, ask for Greenland data , small unique event 4. Aug. 2, 1991: CANOPUS shows large (1400 nT) isolated onset ~06 UT. IMF northward Bz spikes ~0530, ~0550, Large neg. Bz period begins ~05 UT, and gives ~ -114 nT peak DST (at 12 UT) storm. CANOPUS mags. show activity until ~18 UT, when IMF Bz changes sign after very slowly decreasing in magnitude. CRRES data available, apogee near dusk. Forward interpreted data as appropriate to Dr. W. Jeffrey Hughes Center for Space Physics Boston University 725 Commonwealth Ave. Boston, MA 02215 Dr. Larry Lyons The Aerospace Corporation Space Sciences Laboratory P.O. Box 92957, M2-260 Los Angeles CA 90009-2957 Dr. Nelson Maynard Mission Research Corporation One Tara Blvd.; Ste. 302 Nashua, NH 03062 Nelson Maynard (Internet: Maynard@zicon.plh.af.mil SPAN: afglsc::Maynard) Larry Lyons (Internet: Lyons@dirac2.dnet.nasa.gov SPAN: Dirac2::Lyons)