preliminary version, received: 14 September 2000 tent. rev. 19 September 2000 Steve Suess rev. 19 October 2000 Steve Suess JOP132: ULYSSES/SOHO QUADRATURE STUDY Contacts: Giannina Poletto (poletto@arcetri.astro.it) Steve Suess (steve.suess@msfc.nasa.gov) Participants: UVCS/Ulysses/CDS/LASCO SOHO-Ulysses quadratures occur when the SOHO-Sun-Ulysses included angle is 90 degrees: they offer a unique opportunity to compare properties of a plasma parcel observed in the low corona with properties of the same parcel measured, in due time, in situ. UVCS has made several quadrature campaigns since 1997, often in collaboration with other SOHO experiments. In the last quadrature (June 2000) JOP112 was run, focusing on the study of elemental abundances in the corona and in situ. Past observations focused on different issues (e.g. slow, quiet solar wind; low-latitude, variable wind). The Fall 2000 campaign focuses on polar wind, its fine scale structures and CMEs. In November/December 2000 there will not be a true quadrature since Ulysses near the Pole but about 10 degrees behind the Sun, at about 2.4 AU. We expect SOHO instruments to see structures near but just behind the Pole: streamer stalks, streamer brightness boundaries, coronal rays, CMEs, and so on. UVCS will take data outward from about 1.5 R_sun. It is important that other SOHO experiments make observations along the same radial direction from the SUN to Ulysses (see below), that overlap in height and at lower heliocentric distances, to help establish how physical properties of the imaged plasma vary with height. The plan for UVCS involves a sit and stare campaign with an appropriate choice of the grating position(s). If the count rate is high enough, one can consider alternating between two observing altitudes, but this may be decided after initial data are taken. This configuration allows identification of density/plasma speed variations with time (and, possibly, with altitude, if the two alternating positions policy can be adopted). CDS can make rasters, at lower altitudes, to observe lines from the same elements that are covered by UVCS grating position(s) (typically, Oxygen, Si, Fe): CDS may move also sideways, with respect to the radial to Ulysses, to check on variations with positions that might be interesting, even if not directly sampled by Ulysses and, within a limited range, in altitude, to check on changes with height at levels lower than those observed by UVCS. The overall configuration of the solar corona will be provided both by LASCO images and by the UVCS synoptic program. The program focuses, as mentioned, on polar structures. We expect to derive their physical parameters (densities, temperatures, abundances), as done with the 1997 quadrature data (Suess et al. JGR, in press) and with the 98 data (Poletto et al., to be submitted), although techniques used in the past may no longer be applicable, due to the presence of fast wind (e.g.: lack of ionization equilibrium?). Ulysses experiments will provide the physical properties of in situ plasma, to be related with those derived from SOHO observations. Because previous quadratures occurred at times when Ulysses was at lower latitudes, this will be the first study analyzing solar maximum polar plasma sampled first by remote and later on by in situ experiments. The location of Ulysses, as viewed from SOHO, will be as follows: 30 October 2000 (DoY 304): 0.76 deg WEST of heliogr. south (-89.24 deg lat), 11.32 degrees behind the Sun, 2.47 AU 12 November 2000 (DoY 317):0.25 deg WEST of heliogr. south (-89.75 deg lat), 10.08 degrees behind the Sun, 2.38 AU Detailed pdf file plots of the location of Ulysses, as viewed from SOHO during Fall 2000, can be obtained from Steve Suess by emailing him at: steve.suess@msfc.nasa.gov Operational Details: UVCS: UVCS time from 30 October to 12 November has been reserved for this project, shared with other observations. The detailed UVCS plan is attached below. We will take observations with 3-4 different grating positions to cover a spectral range including Lyalpha and O lines. The UVCS slit is long enough to cover different regions: the slit will be normal to the solar radius through the ~ -90 degree latitude, the center will be positioned at that latitude. Quite likely, given the present phase of the solar cycle, streamers will be present at that latitude, but the slit may cover, possibly, coronal holes as well. CDS: CDS is to run sequences on south polar limb regions. It will use a series of rasters with coverage of most of the following lines, on 5,6,8,9 November 04:00 - 18:00 UT.: O V, O VI, Si XII, Mg X, Al XI, N V, Fe X, Fe XII, Ar XII, S X. The STRE4W template is used and 4x4 arcmin rasters that will be shifted back and forth across the south pole, using the NIS detector. Contacts: Andrzej Fludra (fludra@cdso8.nascom.nasa.gov) and Dave Pike (cdp@ast.star.rl.ac.uk). LASCO: In addition to routine observations, extra pB maps may be taken at the time of observations, to help define the morphology of the region under investigation. ------------------------------------------------------------------------------ MEDOC Campaign # 6 (UVCS) ------------------------- Programs involved : Solar max equatorial slow wind (E. Antonucci, A. Gabriel) : hereafter EA SOHO-Ulysses (JOP112 updated to JOP132) (G. Poletto, S. Suess): hereafter GP Prominence coronal environment (D. Spadaro, R. Ventura) : hereafter RV Constraints : EA : UVCS NRT access during the program (i.e. EOF working hours) GP : observations as consecutive as possible ---------------------- Week 1 (30 oct - 5 nov) UVCS planner : RV JOP132 leader : GP and/or S. Suess Times in UT Mond. 30 Oct 00-04 : minisynoptics 04-18 : GP 18-24 : RV Tuesd. 31 Oct 00-04 : minisynoptics 04-18 : GP 18-24 : RV Wedn. 1 Nov 00-14 : SYNOPTICS 14-24 : RV Thursd. 2 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : RV Frid. 3 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : RV Saturd. 4 Nov 00-14 : SYNOPTICS 14-24 : GP Sund. 5 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : RV ---------------------- Week 2 (6 nov - 12 nov) UVCS planner : EA JOP132 leader : GP and/or S. Suess Mond. 6 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : EA Tuesd. 7 Nov 00-14 : SYNOPTICS 14-24 : GP (or EA) Wedn. 8 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : EA Thursd. 9 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : EA Frid. 10 Nov 00-14 : SYNOPTICS 14-24 : EA Saturd.11 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : EA Sund. 12 Nov 00-04 : minisynoptics 04-18 : GP 18-24 : EA ------------------------------------------------------------------------------