Transcript Reimaging Lens Polarization

Solar-B
FPP
The NCAR/HAO Community Spectro-Polarimetric
Analysis Center (CSAC)
Bruce W. Lites
303 497 1517
[email protected]
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Solar-B
FPP
What is CSAC?
• Repository for analysis software for spectro-polarimetric data
• Community involvement/community access
• Full range of analysis:
•
– Calibration
– Inversions
– Ambiguity resolution
– Data visualization
Goals:
– Tested, transportable, documented code
– Conformation to modern software standards
– Computational efficiency
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Why CSAC?
•Spectro-Polarimetric (SP) data has the highest information
content:
•Allows comprehensive, quantitative measures of B
•Permits extraction of line-of-sight gradients
•BUT:
•SP Data is intrinsically more difficult to reduce
•Higher information content means more detailed analysis
•The problem of the past:
Analysis codes have been cumbersome, opaque, not easily
ported to other systems, and not particularly well documented
•CSAC aims to remedy these problems
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Why CSAC?
Widespread interest in spectro-polarimetry: many polarimeters are
new and under-development.
Ground-Based Full Stokes Polarimeters
Type
Developers
Year
Advanced Stokes Polarimeter (ASP)
Imaging Vector Magnetograph (IVM)
Zürich Imaging Stokes Polarimeter (ZIMPOL II)
THEMIS
La Palma Stokes Polarimeter (LPSP)
Tenerife Infrared Polarimeter (TIP)
Polarimetric Littrow Spectrograph (POLIS)
Diffraction-Limited Spectro-Polarimeter (DLSP)
SOLIS- VSM
SPINOR (Visible/IR replacement of ASP)
Swedish 1-m Solar Telescope
ATST Visible/Near IR Polarimeter
Spectrograph
F-P Filtergraph
Flexible
Spectrograph
Spectrograph
Spectrograph
Spectrograph
Spectrograph
Spectrograph
Spectrograph
Spectrograph
Spectrograph
HAO, NSO
U. Hawaii
ETH Zürich
France, Italy
IAC, Spain
IAC, Spain
KIS (Germany), HAO
NSO, HAO
NSO
HAO,NSO
ROYAC, HAO
NSO, HAO
1992
1992
1996
1997
1998
1998
2002
2003
2003
2004
2005
2012
Space-Based Polarimeters
Type
Developers
Year
Solar-B
Solar Dynamics Observatory HMI (SDO)
Sunrise (High Altitude Antarctic Balloon)
Solar Orbiter
Spectrograph
Michelson Filter
Spectrograph, Filter
F-P Filtergraph
Japan/US
Stanford, Lockheed
Germany/US/Spain
ESA
2006
2007
2009
2012
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Some CSAC Priorities
1. Data Reduction Routines:
Develop software for flat-fielding, polarization
calibration, merging, rectification, fringe removal, etc. to prepare data sets for
subsequent inversion.
2. Milne-Eddington Inversion:
This is the workhorse of analysis of SP data
to extract the magnetic field vector (and other associated properties of the
magnetized atmosphere).
3. LILIA Inversion:
Develop standardized, portable software based upon the
SIR (Stokes Inversion by Response functions) procedure. This technique
allows for variation of parameters along the line-of-sight.
4. Rapid Inversion Techniques:
New techniques such as principal
components analysis, neural networks, support vector machines offer
meaningful inversions at a very large increase in speed.
5. Ambiguity Resolution:
CSAC will serve codes for resolution of the 180º
azimuth ambiguity.
6. Data Visualization:
The AZAM utility, as well as other methods for
visualization, will be maintained by CSAC.
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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INVERSION CODE
A More Comprehensive List of CSAC
Inversion Methods
TECHNIQUE
APPLICABILITY
Candidate Zeeman Effect Codes Ready for Inclusion in CSAC
GIMME (Grid
Standard Milne-Eddington
Single or multi-line Stokes
Inversion Method by
model, least-squares fit by
profile observations of
Milne-Eddington)
Marquardt algorithm
photospheric lines, blends
LILIA (LTE based on
Least-squares fitting, LTE
Retrieves detailed depth
Lorien Inversion
1-D atmosphere in HSE
variation of magnetic field
Algorithm)
(comparable to IAC SIR)
and model atmosphere
DIANNE (Direct
Neural Network technique
Must “train” network with
Inversion using
for direct inversion of
observed or theoretical
Artifical Neural
observed profiles
profiles
Networks)
MISMA (MicroLeast-squares, HSE, thin
Optically thin structures,
Structured Magnetic
flux tube approximation
reproduces asymmetries
Atmospheres)
Methods Under Development
NICOLE (Non-LTE
Least-squares fitting, 1-D
Information on L.O.S.
Inversion Code based
atmosphere, chromospheric structure, chromosphere.
on Lorien Engine)
non-LTE line formation
Zeeman effect only.
PROZHAIC
PCA, database of
Encompases Hanle and
(PROminence Zeeman theoretically generated
Zeeman effects in optically
Hanle
profiles
thin case
effect Inversion Code)
SOT #17 Meeting, NAOJ,
April. 2006
ATTRIBUTES
REFERENCE,
STATUS
Robust, slow, limited to
ME model assumptions
Extroardinarily fast,
quantitative accuracy
being evaluated
Skumanich & Lites
1987; widespread
use
Socas-Navarro
2001; Operational,
being improved
Socas-Navarro
(2003); refinement
underway
One physical model
may not apply in all
situations
Sánchez Almeida
1997; working
inversion code
Computationally
intensive; robustness
issues
Applied to He I D3,
10830 prominence
observations
Under
development
Slow, not as robust as
ME inversion
López Ariste &
Casini et al. 2002;
development
continues
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CSAC
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CSAC Data Reduction Routines
•Most SP data has a lot in common:
•Dual beam polarimeters require merging
•Flat-field determination requires care because of spectral lines
•Spectral skew, curvature are common attributes
•Polarimetric calibration variations over the spectral field-of-view
•CSAC has developed codes for data reduction for several
instruments (DLSP, Swedish SP, and now Solar-B)
•Procedures both in IDL and FORTRAN
•FORTRAN routines much faster, allow for real-time processing and
calibration
•Data-specific parameters external to the code
•Simplification of the calling process relieves the user of complex data
processing sequences
•Commonality among instruments of processed data structure
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Solar-B
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Milne-Eddington Inversion Code
•Designed for parallel processing via GRID architecture
•Unlike many problems, the inversion of Stokes data
consists of many separate but identical computational tasks
that require no interaction among them
•This is known as a “scatter-gather” computing problem,
amenable to GRID computation
•The GRID consists of a heterogeneous array of loosely
interconnected individual nodes sharing common resources
•In our case the interconnect is via a network (LAN, or
WWW)
•Code is named Grid Inversion Method by Milne Eddington
(GIMME)
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Inversion Components
GIMME serves as a model for subsequent, more sophisticated
CSAC inversion codes. It consists of 4 components:
1. The Inversion Kernel (IK): A set of libraries of codes (mainly
C, C++) to perform the actual inversion computations
2. The Grid Inversion Server (GIS): An executable, run on the
separate nodes of the Grid, that listens for incoming
commands from the Client to run inversions, then run the IK
libraries for such commands
3. The Grid data server (GDS): An executable that accesses
requests for slices of a data cube, then serve them to the GIS.
If accessed locally, it is a UNIX library. If remote, uses an
OPEnDAP server.
4. The Grid client (GC): A web server application that allows the
user to initiate inversions of either local or remote data sets.
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Stokes Data Inversion
Typical SP data is 4-dimensional:
•Spatial slit scan direction (x)
•Spatial dimension along slit (y)
•Wavelength (λ)
•Polarization (I,Q,U,V)
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Solar-B
FPP
Data Passed by GDS to GIS
•The individual unit of inversion is
the set of Stokes spectra (at right)
•One or more of these may be
passed to the GIS
•The GDS accesses the
entire data volume, and
selects the requested
slice, then passes it to
the various GIS
•Typically, each GIS
receives data from
one slit position
(one x-position, all
y-positions)
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Grid Topology
Example:
•2 local GIS running under Unix sockets
•2 remote GIS running under TCP/IP
•1 local GDS running under NFS
•1 remote GDS running under TCP/IP
SOT #17 Meeting, NAOJ,
April. 2006
•If data sits at llnl.gov: all
4 GIS will be used
•If data sits at ucar.edu:
only 2 local GIS may be
used to access these data
ADDRESS
Protocol
CONNECTION
POINT
hao.ucar.edu
yoda.ucar.edu
abc.llnl.gov
dfg.llnl.gov
data.hao.ucar.edu
data.llnl.gov
Unix socket
Unix socket
TCP/IP
TCP/IP
NFS
TCP/IP
/invert/sockets/hao_socket
/invert/sockets/yoda_socket
Port 2000
Port 2000
/CSAC/data/2003_run
Port 3501
DUTY
inversion
inversion
inversion
inversion
data
data
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CSAC
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Example of Grid Operations
The Client is a web server. For highest efficiency it resides in
proximity to the Grid Inversion Servers so that it may communicate
rapidly and receive results.
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Standards for the CSAC Library of
Analysis Tools
•Codes are highly transportable (written in C, C++), callable from IDL
•Supported under Linux, Solaris
•Efficient coding, appropriate for parallel architecture
•Well documented, commented, and tested
•Flexibility to accommodate data from a wide variety of instruments
•Standardized input/output
•Standards for presentation in solar coordinates
•Filters provided to convert input data from major instruments (Solar-B,
DLSP, SOLIS, etc.)
•Codes maintained at a HAO/NCAR
•Examples of input/output data provided
•Open source for user modification, experimentation, and community
input
•Online access to all analysis tools
•User forum for suggested modifications, additions
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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Solar-B
FPP
SOT #17 Meeting, NAOJ,
April. 2006
The AZAM Utility
Lites
CSAC
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The AZAM Utility
•Interactive, manual resolution of the 180º azimuth ambiguity
•Flexible display of inversion parameters
•Color images
•Arrows
•Blinking images against one another
•Contour plots
•Interactive display of data: images, spectral profiles,
•And much more………………
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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FPP
Advanced Inversion Methods
Advanced inversion
techniques allow extraction
of the field vector from the
photosphere into the
chromosphere from
simultaneous
measurements of
photospheric lines and the
Ca II IRT lines
Measured electric current
density at heights 200, 650, and
1600 km – Socas-Navarro 2005,
ApJ 633, L57
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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CSAC Outlook for the Coming Year
1.
Finish GIMME Milne-Eddington Inversion, prepare for analysis of SolarB data
2.
Implement Artificial Neural Network initialization for GIMME
3.
Implement LILIA detailed inversion
4.
Generalize AZAM to accept data from GIMME (i.e., from any data
source)
5.
Implement the simulated annealing azimuth ambiguity resolution for
automatic processing
6.
Host a community workshop to address community needs
7.
Sponsor graduate student visits
SOT #17 Meeting, NAOJ,
April. 2006
Lites
CSAC
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