FASR Science Simulations
AGU/SPD Splinter Meeting
22 May 2005
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Science Goals Table
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Role of Simulations
Two types of simulations
• Array Configuration Simulations
– determine “best” configuration to meet imaging goals
– quantify trade-offs in site selection, antenna
constraints
• Science Simulations
– determine FASR performance for certain science
goals
– determine observing strategies
– determine calibration strategies
– develop image processing algorithms
– develop data analysis algorithms
– guide to data visualization
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Simulation Levels—Level 0
• Images with complex structure, but no
attempt at physics input or correct spatial
scales.
• No frequency dependence.
• Examples are the FASR logo and TRACE
partial frame images done by T. Bastian.
• These are of limited usefulness.
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Level 0 Example,
Bastian TRACE Loops
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Level 1
• 2D Full-Sun models based on T, EM maps from
TRACE/EIT or other input.
• Frequency dependence of brightness, scattering size,
and shape may be included.
• Example is S. White’s SPIE paper, with set of radio
images at several frequencies.
• Magnetic field component may be added based on MDI
longitudinal magnetogram, and T, EM is limited to
TRACE/EIT diagnostic range.
• These are useful for assessing performance of different
configurations and different image reconstruction
algorithms.
• Frequency dependence is for frequency-dependent
spatial scales only, and not for spectral diagnostics.
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Level 1 Example,
Stephen White’s Full Disk Sims
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Level 2a
• Targeted physics-based 3D model with some limitation,
such as limited spatial extent, or limited frequency range,
but based on T, EM or ne, vector B with correct radiative
transfer.
• Examples include D. Gary’s magnetic field model (based
on Mok active region model), S. Tun’s coronal cavity
model (based on Low analytical model), M.
Aschwanden’s hot loop model, and Z. Liu’s type III
model.
• These are useful for exploring physical diagnostics, but
may be misleading due to lack of correct spatial scales,
omission of confusing sources, or limited applicable
frequency range.
• These are NOT useful for assessing performance of
configurations, but may be useful for studying algorithms
and are certainly good for PR.
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Level 2a Examples
Aschwanden Loops, Gary AR Model
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Level 2b
• Same as level 2a, but with dynamics added.
• These may be useful for assessing FASR time
resolution for electron time of flight (ms
timescale), or CME difference imaging (minutes
timescale), type II, III, and U bursts, sunspot
oscillations, filament eruptions, etc.
• We have no examples of this type yet. These
have major implications for PR, however, and
are needed for Level 4, below.
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Level 3
• Full-Sun 3D models with embedded 3D physics-based
models from level 2.
• What is envisioned here is the placement of isolated AR,
hot loop, flaring loop, filament, CME, and other models
into a full-disk model (with chromospheric network?)
• Requires the ability to vary the geometry (placement) of
the isolated models so that the effect of viewing angles
can be studied. Such physics-based full-Sun models are
essential for development of the algorithms and datahandling software, and to understand the limitations of
the configuration and sensitivity on extraction of
diagnostic information.
• For seamless insertion of embedded models, a
geometrical framework is needed, including non-uniform
gridding.
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Level 4
• To assess the interplay between time resolution
and sensitivity limitations, we need to add
dynamics to any or all of the embedded models.
• This includes flaring loop dynamics, particle
transport and loss mechanisms, expanding CME
geometry, filament eruptions, sunspot
fluctuations/oscillations, network microflares,
and so on.
• This level is also required for exercising of datahandling and real-time algorithms.
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What is Needed for DDP?
• Configuration studies will require Level 1
models. Stephen will address this.
• Additional target-physics Level 2 models,
especially with time dependence (Level
2b), but with allowance for transition to
Levels 3 and 4 (i.e. think about what is
needed for embedding into full Sun
geometry).
• At least one Level 3 (full Sun) model is
needed, with software for embedding.
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