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Russia_2006 Current STELab IPS Heliospheric Analyses STELab interplanetary scintillation (IPS) 327 MHz array near Fuji IPS and SMEI Observation Comparison
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Russia_2006 Scintillation Level (g-level) Heliospheric Analysis Intensity interplanetary scintillation (IPS) g-levels. IPS and SMEI Observation Comparison
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Russia_2006 IPS 3D Reconstruction 20 May – 05 June 2003, (28 May ‘Halo’ CME) IPS and SMEI Observation Comparison | Pressure (ρ = CnV 2 ) Observations at Mars
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Russia_2006 CSSS Model Inclusion into the Tomography IDEA ! Problem – the most fundamental parameter magnetic field is unknown. IPS and SMEI Observation Comparison (Grad. student Tamsen Dunn)
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Russia_2006 Bastille Day Event Period 2000/ 07/14 corr. 0.9+ when in situ response smoothed by 7 days IPS and SMEI Observation Comparison
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Russia_2006 IPS C.A.T. Analysis IPS and SMEI Observation Comparison
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Russia_2006 Time Series for 3 Models and 18-hr Avg. In Situ Data for CR 1965 IPS and SMEI Observation Comparison
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Russia_2006 Faraday Rotation IPS and SMEI Observation Comparison
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Russia_2006 Measured values of the magnetic field as a function of distance of spacecraft through the magnetic cloud. The red lines are the best fit of the simple cylindrically symmetric flux rope model to the observations. Method 1.Fit observed flux rope at 1 AU with simple flux tube model 2.Map flux tube back to Sun at constant speed 3.Scale flux tube dimensions linearly 4.Calculate RM due to rope every 10 minutes Magnetic Cloud Model Simulation (Justin Kasper LWS, Boulder 2004) IPS and SMEI Observation Comparison
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Russia_2006 Simulations of Observations During Transit (a) (b) (a-f): Images of the rotation from the first flux rope that LOFAR-type instrument would have observed as a function of time since the eruption of the CME. The clock indicates the time since the CME erupted. The pixel color indicates the Faraday Rotation at 60 MHz (Note that the scale changes for each image!). In (a), the rope has not yet produced an observable change in the rotation, and the ~2 degree uncertainty of the LOFAR measurements is apparent. In (b) approximately 20 sources have undergone very large rotations. The rope gradually expands to fill the sky in (c-e). In (f) Earth is inside the flux rope. (Justin Kasper, LWS, Boulder 2004) IPS and SMEI Observation Comparison
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Russia_2006 (c) (d) (e)(f) (Justin Kasper LWS, Boulder 2004) IPS and SMEI Observation Comparison
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Russia_2006 The MILEURA WIDEFIELD ARRAY (MWA) A joint US-Australia project IPS and SMEI Observation Comparison Kick-Off meeting San Diego 4-7 June 2006
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Russia_2006 PARTNERS AND COLLABORATORS PARTNERS MIT: Haystack Observatory and Center for Space Research Harvard-Smithsonian Center for Astrophysics Australia Telescope National Facility (ATNF) University of Melbourne (AU) Australian National University (AU) Curtin University of Technology (AU) Office of Science Innovation (Western AU Govt.) COLLABORATORS in HELIOSPHERIC SCIENCE University of California, San Diego Nagoya University/STEL, Japan University of Bonn, Germany University of Sydney, Australia AF Research Laboratory MWA: A joint US-Australia project IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 MILEURA WIDEFIELD ARRAY (MWA) – LOW FREQUENCY DEMONSTRATOR (LFD) Mileura, Western Australia - RFI environment - Infrastructure flexibility General Characteristics: ▪ Frequency coverage: 80-300 MHz ▪ Wide field (~1000 deg 2 ) ▪ A science-focused demonstrator ► Conduct key science experiments ► Demonstrate technology Projected schedule : ► 2005: Prototype field tests ► 2006-07: Construction ► 2008-09: Scientific observations Project status: Approved for funding – formal award expected 1 June IPS and SMEI Observation Comparison (Joe Salah) (At Australian proposed SKA Site)
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Russia_2006 SCIENTIFIC MOTIVATION THREE FOCUSED EXPERIMENTS: Measurement of red-shifted 21 cm power spectrum from the Epoch of Reionization in the early universe. Observation of the solar wind structure from near the Sun to 1 AU Interplanetary Scintillations Faraday Rotation: emphasis on CME magnetic field Type II solar burst imaging Detection of radio transients IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 MWA-LFD SPECIFICATIONS Frequency: 80-300 MHz 500 antenna ‘tiles’, each with 4 x 4 crossed dipoles Imaging field of view: 50 o -15 o (80 - 300 MHz) Phased array mode: 16 beams Total collecting area: 8000 m 2 (at 200 MHz) Bandwidth: 32 MHz Sensitivity: ~20 mJy for 1 sec int. (at 200 MHz) Spatial extent of array: 1.5 km core + extensions to 3 km Resolution: ~2 arcmin (at 200 MHz) Polarization: Full Stokes IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Physical Layout of Array Core Central Processor IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Core Antenna tile AUGMENTATION FOR SOLAR BURST IMAGING INITIAL SUB-ARRAY AT MILEURA: ~ end 2007 Angular resolution: 2 arcmin (200 MHz) Time resolution: 50 msec (temporary) Frequency resolution: 64 KHz across 4 MHz band IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 B. Jackson and P. Hick (UCSD), M. Kojima (STEL) MWA-LFD will provide: An increase in the number of independent observations (beams) by factor of 16 – this addresses the most constraining bottleneck in IPS Enhanced sensitivity by a factor ~5 with an increase in number of IPS sources observed Increased spectral SNR (factor of 3-4) due to longer observation times allowed by the independent beams Coverage in southern hemisphere and new longitude adding to global IPS coverage (STEL, EISCAT, OOTY, MEXART) IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 PRINCIPLE OF FARADAY ROTATION (FR) Technique has been successfully applied using spacecraft telemetry signals (2.3 GHz) (Pioneer,Helios, Cassini) as spacecraft pass behind Sun (Bird, Pätzold, Jensen...) or with VLA (1.5 GHz) observing galaxies through heliosphere (Mancuso, Spangler…) For the MWA: Estimate 1 polarized source per 3-4 deg 2 (Haverkorn et al.) Potentially higher resolution using polarized galactic background = 60° at 300 MHz = 800° at 80 MHz For RM = 1 rad m -2 Rotation Measure (RM) IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Challenges for the application of Faraday rotation Detailed survey for polarized sources at 80-300 MHz in Southern Hemisphere Unfold rotation ambiguity –Use multiple frequencies within array band Remove rotation effects due to the Earth’s ionosphere: –Use GPS for absolute calibration (AFRL contribution acknowledged) –Use array calibration for small scale distortions across array Invert Faraday rotation to determine B –Need measurement of plasma density [IPS, SMEI, STEREO] –Demonstrate algorithms and accuracy (UCSD collaboration) Demonstrate from ground to confirm overall accuracy (~4 o for 20 mJy in 5 min) Operations: –Need trigger (external, radio burst) to prompt FR observations of event at high cadence IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 SOLAR BURST IMAGING Type II solar bursts are generally associated with fast CMEs and shocks, are usually observed at frequencies below 150 MHz and drift at ~ -0.2 MHz/s, lasting many minutes. The frequency-time structure of Type II bursts has been well characterized through past observations. In order to make further progress in understanding their relationship to CMEs, information on spatial structure (images) and location are needed. The augmented MWA-LFD has wide field-of-view, high dynamic range snapshot-imaging capability, and angular resolution to observe solar Type II bursts. The ~2 arcmin angular resolution will allow precise location of the bursts. IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Early Deployment Tests at Mileura (March-September 2005) The first antenna tile at Mileura Early Deployment Tests conducted by ANU, Curtin Univ., Univ. Melbourne, and MIT IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Deep integrations for 60 min RFI environment at Mileura 102 MHz 131 MHz 189 MHz 327 MHz 187 MHz Deep integration for 10 hours IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 25 Interferometry tests (2 and 3 antenna tiles – 145 meters) Correlated amplitude and phase on Sun (96 MHz) on 27 April 2005 IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 15 September 2005 04:53 04:56 04:59 05:03 05:06 05:10 05:13 UT TIME Each panel = 60 seconds Res: 50msec FREQUENCY 98.5-102.5 MHz Color: signal amplitude in dB, spanning a range of ~12 dB. MWA-LFD SOLAR BURST OBSERVATIONS Res: 16 kHz IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 SUMMARY Measurements of large scale structure in solar wind plasma, and tracking of CMEs from ~0.25 AU to 1 AU and beyond through IPS. Characterization of heliospheric magnetic field, and determination of the evolution of CME magnetic field through Faraday rotation as a key input to space weather predictions. Imaging of Type II bursts with fine angular resolution (~2 arcmin) ANTICIPATED MWA SCIENCE RETURNS FOR HELIOSPHERIC SCIENCE: The Mileura Widefield Array (MWA) is a new-generation low frequency radio sensing instrument, enabled by modern digital signal processing, high speed signal transport, and powerful computing. Characteristics: high sensitivity, wide-field coverage, multiple beams. Location: extremely radio-quiet site in Western Australia Planned operation: initial phase by ~end-2007, full system 2008. IPS and SMEI Observation Comparison (From Joe Salah)
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Russia_2006 Still needed: a) A lot more work. b) SMEI - 3D reconstruction analysis from the whole time period observed by SMEI and comparison with IPS. c) Inversion of the Faraday Rotation observations to determine and remotely-sense 3-component magnetic fields. d) Work on the SKA LFD (MW array telescope), Faraday rotation, Ionisphere: Who wants to help? Summary: IPS and SMEI Observation Comparison
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