SH11A-01 INVITED 08:00h
Three-dimensional structure of compound interplanetary transients associated with 27-28 May 2003 coronal mass ejections
We have investigated the global features of interplanetary (IP) disturbances associated with 27-28 May coronal mass ejection (CME) events using interplanetary scintillation (IPS) measurements of the Solar-Terrestrial Environment Laboratory (STEL). Our IPS data taken between 2003 May 28 22h UT and May 29 7h UT showed a set of complex feature of IP disturbances, and most of them are regarded as IP consequences of two full-halo CMEs which occurred in association with the X1.3/2B flare on May 27 23:07 UT and the X3.3 flare on May 28 00:27 UT. Some components of the IP disturbances were discriminated from the IPS data by making the model fitting analysis iteratively. One of the components was an Earth-directed one, which appears to correspond to the IP shock observed by ACE on May 29 18:30 UT. Other components were obliquely propagating ones, which either preceded or followed the Earth-directed one. The global features deduced here are generally in agreement with heliospheric reconstructions made from Solar Mass Ejection Imager (SMEI) measurements.
SH11A-02 INVITED 08:15h
Heliospheric Photometric Images and 3D Reconstruction from the Solar Mass Ejection Imager (SMEI) Data
The Solar Mass Ejection Imager (SMEI) experiment is fixed to the Coriolis spacecraft and views the sky above Earth using sunlight-rejecting baffles and CCD camera technology. SMEI was designed to provide precise photometric white light images over most of the sky on each 102-minute Earth orbit. The brightness sky maps of the inner heliosphere indicate a rich variety of electron density structures that are produced by the material that propagates through it and its interaction with ambient structures. We present some of the preliminary results of the analysis of these photometric SMEI observations derived by modeling the white light observations such that most of the contaminant signals: stars, the zodiacal cloud and high-energy particle variations are removed. We will also show some of the 3D reconstructions that allow this contaminant signal removal using both interplanetary scintillation (IPS) and SMEI data.
http://cass185.ucsd.edu/smei/smei.html
SH11A-03 INVITED 08:30h
CMEs Observed in the Heliosphere by the Solar Mass Ejection Imager (SMEI)
The Solar Mass Ejection Imager (SMEI) experiment on the Coriolis spacecraft has been obtaining all-sky, white light images on each 101-minute orbit for over 1.5 years. SMEI is fixed to the spacecraft and views the sky above Earth using sunlight-rejecting baffles and CCD camera technology. When fully calibrated, sky maps of structures having enhanced electron density in the inner heliosphere can be produced. We present some preliminary results of analysis of SMEI observations of coronal mass ejections (CMEs) traveling through the heliosphere. These include observations of about 100 CMEs during the first full year of observations. At least 3 of these, observed as frontside halo events by LASCO, were observed by SMEI propagating to and beyond 1 AU, and were associated with major geomagnetic storms at Earth. We will show examples of the CMEs and present a summary of their characteristics. We will also show some 3D reconstructions using both interplanetary scintillation (IPS) and SMEI data using techniques being developed to analyze the evolution of heliospheric plasma, including transient CMEs and corotating dense regions.
SH11A-04 08:45h
Earthbound and Geoeffective CMEs Observed by the Solar Mass Ejection Imager (SMEI)
During its $\sim$2 year lifespan, well over 100 CMEs have been detected and tracked by the Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft. Of these, a small number have been identified as halo (Earthbound) CMEs, while other events have coincided with halo CMEs observed in coronagraphs and shocks observed by solar-wind based spacecraft. Some have also resulted in geomagnetic storms upon arrival at the Earth. We present a survey of probable Earthbound CMEs, using over 18 months of SMEI data correlated with coronagraphs, magnetometers and particle detectors. These instruments include the LASCO and EIT instruments aboard SOHO, SWEPAM and MAG aboard ACE and ground-based magnetometers providing Kp and Dst indices. Acceleration rates, common features, and the use of SMEI as a potential space weather forecasting tool are discussed.
http://www.sr.bham.ac.uk
SH11A-05 09:00h
Wind/WAVES and SMEI Observations of ICMEs
The low-frequency (kilometric) radio observations on Wind/WAVES provide important spectral and directional information related to the propagation of ICMEs through interplanetary space. However, up to now there has been no white-light observations with which to compare these low-frequency interplanetary radio observations, beyond the 30 Rs limit of the LASCO field of view. The recently launched Air Force Coriolis spacecraft that includes the Solar Mass Ejection Imager (SMEI), which is the first all-sky camera designed to track ICMEs from the Sun to 1 AU, provides a unique opportunity of simultaneously tracking CMEs, both in white light and in radio, all the way from the corona to 1 AU. 3D reconstruction techniques, utilizing multiple perspective views of the ICME observed by SMEI, represent the propagation and evolution of these density structures through the 3D heliosphere. There are two general ways that the Wind/WAVES radio data can be directly related to the SMEI heliospheric white-light observations. First, since the observed radio frequency depends on the local plasma density in the radio source region and since the interplanetary plasma density falls off with the inverse of the heliocentric distance squared, the observed radio frequency generated by the CME/shock decreases as the type II radio source associated with the CME propagates farther from the Sun. Thus the frequency characteristics of the type II radio emissions provide information on the radial distance of the ICME. Secondly, the low-frequency radio receivers on the Wind spacecraft have the unique capability of providing information on the direction of arrival of the radio emissions and of the size of the radio-emitting region. Both of these results, obtained from analyses of the Wind/WAVES radio observations, will be directly compared with the results from the analyses of the SMEI white-light data for various ICME events.
SH11A-06 INVITED 09:15h
Observations of High Altitude Aurora With the Solar Mass Ejection Imager
The Solar Mass Ejection Imager (SMEI) is a sensitive satellite-mounted heliospheric scanning instrument which assembles an approximately all-sky image in red-biased white light once per orbit. Its lines of sight pass obliquely through the topside ionosphere and magnetosphere. We present serendipitous observations of a visual phenomenon detected at high altitudes ($\geq$ 840 km) over the polar caps. The observations represent both transits of the satellite through a luminous medium and remote viewing of columnar structures possibly extending to heights of 2000 km or more. More than 1000 occurrences of these phenomena were recorded in the first year of operations, from February 2003 to February 2004. These observations are well correlated in brightness and frequency with periods of enhanced geomagnetic activity.
SH11A-07 09:30h
Systematic Error Reduction and Photometric Calibration for the Solar Mass Ejection Imager (SMEI)
The Solar Mass Ejection Imager (SMEI) instrument provides white-light photometric maps covering most of the sky each orbit of the Coriolis spacecraft. The SMEI differential photometry specification is 0.1% for each 1 square degree sky bin. A labyrinthine baffle reduces scattered sunlight, but for a portion of the data a background residue must also be subtracted to finally reach this specification. We describe this process, and further discuss how bright stars are used to determine an appropriate conversion from the CCD-camera data units to sky surface brightness. Also, the CCD in the camera viewing closest to the Sun operates significantly warmer than expected, which gives rise to a changing population of "hot pixels". We describe a data-analysis process which significantly alleviates the photometric impact of this.
http://cassfos02.ucsd.edu/solar/smei_new/index.html
SH11A-08 INVITED 09:45h
Heliospheric Imagers for Tracking Coronal Mass Ejections: Lessons Learned from the Solar Mass Ejection Imager
The Solar Mass Ejection Imager (SMEI) was launched on board the DoD Space Test Program's Coriolis satellite on January 6, 2003. The SMEI instrument represents a new kind of imager designed specifically to observe Coronal Mass Ejections (CMEs) and other dense structures in the solar wind as they propagate through the heliosphere. Its viewing range starts at 20 degrees elongation from the Sun and extends to beyond 1 A.U.. More than 120 CMEs have been detected with the SMEI instrument, including three well-documented "halo" events that led to geomagnetic storm conditions on Earth. These observations demonstrate the potential of a heliospheric imager for space weather specification and prediction purposes. More than halfway through SMEI's planned three-year lifetime, we look ahead towards an operational heliospheric imager. We will briefly reveal some of the lessons learned from the SMEI mission and offer recommendations for a future system with operational capability.