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M. M. Bisi(I), B IPIPSS oobbserservavationstions ofof tthhee innerinner--helioheliosspherpheree anandd theirtheir ccomomppaarisrisoonn wwiithth multi-multi-popointint in-in-ssituitu mmeaeassurementsurements M. M. Bisi(i), B. V. Jackson(i), A. R. Breen(ii), R. A. Fallows(ii), J. Feynman(iii), J. M. Clover(i), P. P. Hick(i), and A. Buffington(i) (i)(i) CCenenteterr foforr AsAstrotrophyphyssicicss aandnd SSpacpacee ScScieiencncees,s, UUnivniveerrsisityty ofof CCalifoaliforrnia,nia, SSanan DDieiego,go, USAUSA (ii)(ii) InsInstittituteute ofof MatheMathematicmaticaall aandnd PPhyhyssicicalal ScScieiencncees,s, AAbeberryysstwtwyythth UnUniviveersrsiityty,, WaleWaless,, GBGB ((iiii)ii) JJeett PrPropulsopulsiionon LaborLaboraatortoryy,, CCalifaliforornia,nia, USAUSA AAbbsstratracctt Interplanetary scintillation (IPS) observations of the inner-heliosphere have been carried out on a routine basis for many years using metre-wavelength radio telescope arrays. By employing a kinematic model of the solar wind, we reconstruct the three-dimensional (3D) structure of the inner-heliosphere from multiple observing lines of sight. From these reconstructions we extract solar wind parameters such as velocity and density, and compare these to ªground truthº measurements from multi-point in situ solar wind measurements from ACE, Ulysses, STEREO, and the Wind spacecraft, particularly during the International Heliophysical Year (IHY). These multi-point comparisons help us improve our 3D reconstruction technique. Because our observations show heliospheric structures globally, this leads to a better understanding of the structure and dynamics of the interplanetary environment around these spacecraft. 11.. IIntenterrpplalanneetataryry SSccinintillatillattioionn Interplanetary Density irregularities carried out by the Two-station IPS measurements are solar wind modulate the signal from a Scintillation (IPS) is where simultaneous observations distant radio source, e.g. Quasar. the rapid variation in are made of the same source by radio signal from a widely separated antennas. compact source Using two stations for IPS produced by variations in the solar wind allows the solar wind velocity density. to be measured to a high degree of accuracy. Measurements of IPS allow the solar wind The example used here is of an EISCAT (European velocity to be observed Scintillation patterns over a wide range of received at antennas. Incoherent SCATter radar) heliographic latitudes telescope and a MERLIN (Multi-Element Radio and at distances from 0319+415, 2004/05/12 the Sun currently Tromsù -Jodrell Bank Linked Interferometer inaccessible by Network) telescope. There spacecraft - no other are also many other IPS- observing method has capable systems used. the unique capabilities of IPS. Hubble Deep Field ± HST (WFPC2) 15/01/96 ± Courtesy of R. Williams and the HDF Team and NASA Density values for the solar wind can be inferred from the `scintillation level' (g-level) of IPS observations. Velocity resolution improves as the parallel baseline increases ± but in contrast ± the correlation between the sites decreases as turbulence evolves within the solar wind due to the increased time-lag between observing sites. Cross- and auto- power spectra can be Different baselines can be used fitted using a 2D weak-scattering depending on the geometry of the IPS model developed by W.A. Coles at raypath and a large parallel baseline UCSD and extended to treat (Bpar) to perpendicular baseline (Bperp) multi-frequency observations at ratio is needed for correlation between Aberystwyth University. the two sites. 22.. TThhee IPSIPS TeTeleslesccoopespes/Ar/Arrraayyss useusedd inin ththisis StuStudydy From left-to-right: the Ooty telescope, STELab (Fuji, Sugadaira, old Toyokawa antenna, and Kiso) IPS arrays, and the new Toyokawa IPS array; all observe at 327 MHz. The EISCAT/ESR telescopes from left-to-right: Tromsù, Kiruna, Sodankylä Solar-Terrestrial Environment Laboratory (http://www.eiscat.com/sodan.html), and the ESR. (STELab) in Japan (courtesy of M. Kojima et al.) are primarily used for 3D reconstructions, and Ootacamund (Ooty) Radio Telescope (ORT) in India (courtesy of P. K. Manoharan) and EISCAT/ESR/MERLIN IPS data are also used here for 3D reconstructions. 33.. TThhrreeee--DimDimeensionsionalnal RRececoonstrnstruucctiotionnss Heliospheric Computer- Aided Tomography (C.A.T.) analyses showing the line-of-sight 13 July 2000 distribution for each sky location during mid-July 2000 from STELab IPS observations. Heliospheric C.A.T. Analyses: 14 July 2000 IPS line-of-sight weighting values for each sky location (right). 44.. NoNovveemmbeberr 22000404 GeGeoommaaggnneetictic StStoorrmmss During the period of early November 2004, there were two large geomagnetic storms that impacted on the earth, these occurred on 2004/11/08 and 2004/11/10. The 2004/11/08 geomagnetic storm was probably caused by the 2004/11/04 CMEs as seen in SOHO|LASCO C2. The 2004/11/10 geomagnetic storm was probably caused by the 2004/11/06 and 2004/11/07 CMEs, also seen in SOHO|LASCO C2. This period was a time of complex solar magnetic activity. (i) Combination of the 6 November 2004, 01:32 UT (halo) and 02:06 UT, LASCO C2 CMEs. (ii) Front edge of the 8 November 2004 geomagnetic storm most likely caused by a combination of Earth-directed CMEs seen in LASCO on 4 November 2004 at 09:54 UT and 23:30 UT. (iii) High speed structure engulfing the Earth which lags the 6 November 2004 Earth-directed events (01:32 UT halo CME and 02:06 UT partial-halo CME) but precedes the 7 November 2004 event. From Harra et al., 2007. (iv) High speed structure going mainly Northward. Density values (left) as compared at ACE reconstructed using Ooty g-level data. STELab speed (right) values as compared at ACE. From Bisi et al., 2007. Three-dimensional reconstructions from both Ooty and STELab data give mixed results when compared in situ, but the 3D structures seen in the STELab 3D reconstructions are consistent with the timing of the CMEs seen in SOHO| LASCO C2. 3D reconstructions using Thomson-scattered white-light data from the Solar Mass Ejection Imager (SMEI) yield better in situ comparisons in terms of density as discussed in Bisi et al., 2007. 55.. UUllyysssseess QuaQuaddrraatuturree ±± AprApriil/Mal/Mayy 22000077 ±± PrPrelimeliminainarryy 3D3D ReReccoonnsstrtruucctiotionnss EISCAT/ESR/MERLIN (E/E/M) speed reconstructions and STELab speed and density reconstructions. E/E/M compared with Advanced Composition Explorer (ACE) in situ measurements and STELab compared with both ACE and Ulysses in situ measurements. Preliminary analyses of E/E/M data show a reasonable comparison over a limited time when compared with the ACE measurements, but unfortunately provided no comparison with Ulysses at present. Preliminary analyses of STELab data (which was incomplete during this period) gave reasonable comparisons with ACE velocity and some similarity with Ulysses velocity measurements, but did not do so well when compared in density with data taken by ACE or Ulysses. 66.. UUllyysssseess CloClossee PasPasss ±± AugAuguusstt 22000077 ±± PrePrelimliminarinaryy 33DD ReReccoonnsstrtruucctionstions Preliminary analyses of STELab IPS data reconstructions as compared to ACE and Ulysses in situ measurements. STELab suffered various data outages during this period, so the IPS data were ªspottyº at best, and hence were split into two time periods as shown throughout the Ulysses close pass to the Sun. All reconstructions compared with ACE and Ulysses in situ values. 77.. SuSummmmaarryy aanndd FuFutureture WoWorrkk · Detailed study into the overall 3D structure of the reconstructions is needed to test how well the model reconstructs the inner heliosphere, and not just a comparison with ACE and/or Ulysses in situ measurements ± this can be accomplished with the incorporation of STEREO spacecraft comparisons (coming soon). · ªTweakingº of the model to more-accurately process the Ooty data in particular. · Incorporation of velocity data into the Ooty reconstructions to improve the timing of the peaks (events). · More complete IPS data would yield better quality reconstructions ± particularly before periods of interest. · Incorporating the third SMEI camera data may improve the timing and magnitude of the reconstructed peaks. Primary References: Bisi, M.M., B.V. Jackson, P.P. Hick, A. Buffington, and J.M. Clover, ªCoronal Mass Ejection (CME) Reconstructions from Interplanetary Scintillation (IPS) Data Using a Kinematic Model: A Brief Reviewº, 4th Asia-Oceania Geophysical Society General Assembly Proceedings, Advances in Geosciences, submitted September 2007. Harra, L.K., N.U. Crooker, C.H. Mandrini, L. van Driel-Gesztelyi, S. Dasso, J. Wang, H. Elliott, G. Attrill, B.V. Jackson, and M.M. Bisi, ªHow does large flaring activity from the same magnetic field configuration produce oppositely directed magnetic clouds?º, Solar Physics in-press, 2007. Klinglesmith, M., ªThe Polar Solar Wind from 2.5 to 40 Solar Radii: Results of Intensity Scintillation Measurementsº, Ph.D. Thesis, University of California at San Diego (UCSD), 1997..
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