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Solar and STP science Solar and STP science with AstroGrid with AstroGrid
Silvia Dalla
School of Physics & Astronomy, University of Manchester
A PPARC funded project
Science questions
• Solar: energy transfer from magnetic fields to the plasma in the corona (coronal heating)
• Transient energy release events: solar flares, coronal mass ejections (CMEs)
• STP (=Solar Terrestrial Physics): the Sun's influence on the Earth environment – geomagnetic storms, space weather
AstroGrid and solar/STP
• Apply processing tool over a large number of events – allows statistical studies, rather than based on a few events.
• Observe solar features in multiple wavelengths.
• Allow work involving solar (images), interplanetary, magnetospheric, ionospheric (time series) datasets.
• Link models with data.
Solar datasets and tools
• MSSL SURF archive: SOHO/CDS and TRACE
• Virtual Solar Observatory: SOHO/EIT
• EGSO: Solar Event Catalogue (SEC)
• Solar tools:
• Solar Movie Maker• Solar Overlay• Generic Movie Maker
Solar Movie Maker Service
New tool: Time Cross Matcher
• Modification of the 'standard' AstroGrid X-Matcher so that 2 catalogues can be matched on the basis of event time.
• Example: Catalogue of Soft-X-ray flares (GOES), characterised by start/end times and several other parameters.
• Time-X-match with catalogue of hard-X-ray flares observed by RHESSI spacecraft.
GOESGOES +RHESSI
STP study: Geoeffectiveness of CMEs
• Investigate the chain of events starting with a CME at the Sun, and leading to a geomagnetic storm and aurora at the Earth.
• Can we predict if a CME will hit Earth and cause a geomagnetic storm? Space weather.
• How is this process influenced by conditions in the interplanetary medium ?
with Mike Pinnock, Ian McCrea (RAL) et al
STP study – cont’d
• Query catalogue of halo CMEs
• Retrieval of interplanetary magnetic field and solar wind data (ACE spacecraft) [t-series]
• Retrieval of geomagnetic indeces
(RAL) [t-series]
• IDL tool extracting time series parameters (DST < 75? geoeffectiveness = 1) and making a summary plot
• Summary votable constructed including CME, interplanetary, geomagnetic parameters
Solar study 1: type III productive hard X-ray flares
• Aim: compare flare emission at radio and hard X-ray wavelength.
• Test the hypothesis that type III radio emission tends to be associated with hard X-ray flares of hard electron spectral index.
with Lyndsay Fletcher (Glasgow)
Type III burst
Solar study 1 - contd
• Access RHESSI fits data.
• IDL tool calculates spectral ratio for RHESSI flares.
• Time X-match radio type III and Hard-X-ray votables
B. Dennis GSFC
Solar study 2: Are Active Regions emerging near existing ARs more flare-productive?
• New active regions emerge on the solar disk every day
• Flare productivity increases with magnetic complexity in an AR.
• Is an AR emerging on disk near another one, more likely to produce flares than an isolated AR?
with Lyndsay Fletcher (Glasgow)
Solar study 2: contd
• Multiple queries to Active Region catalogue in a workflow loop, to establish ARs emerging on visible disk (rather than rotating into view)
• Define a region of given radius around newly emerged AR – any other ARs ?
• Time X-match votable of ARs with flare catalogue -> establish flare productivity
Conclusions and future work
• AstroGrid workflow environment is a powerful tool for developing solar and STP studies involving a large number of events, and requiring multiple catalogues and datasets.
• Time X matcher a very useful tool for Solar/STP.
• In the next few months, expand range of datasets available.
• First example of STP model running as CEA application: CTIP model developed at UCL.
• Standardise access to time-based datasets.
• Provide helper application for display of time series data.