Far-side Imaging and Activity Irene González Hernández and the GONG and MDI far-side teams...
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Transcript of Far-side Imaging and Activity Irene González Hernández and the GONG and MDI far-side teams...
![Page 1: Far-side Imaging and Activity Irene González Hernández and the GONG and MDI far-side teams National Solar Observatory, Tucson, AZ Stanford University,](https://reader035.fdocuments.in/reader035/viewer/2022062517/56649f265503460f94c3dc54/html5/thumbnails/1.jpg)
Far-side Imaging and ActivityFar-side Imaging and Activity
Irene González Hernández and the GONG and MDI far-Irene González Hernández and the GONG and MDI far-side teamsside teams
National Solar Observatory, Tucson, AZNational Solar Observatory, Tucson, AZStanford University, Stanford, CAStanford University, Stanford, CA
Northwest Research Associates (CORA), Boulder, CONorthwest Research Associates (CORA), Boulder, CO
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ContentsContents Introduction to far-side seismic holography
Improving the far-side maps
Calibrating the seismic signal
Success Rate
Variation of the mean phase with the solar cycle !
Improving the signal to noise
Future work and conclusions
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Helioseismic Imaging of the Helioseismic Imaging of the FarsideFarside
Helioseismic imaging of sunspots at their antipodes. Lindsey, C. Helioseismic imaging of sunspots at their antipodes. Lindsey, C. & Braun, D.C, 1990, SoPh.& Braun, D.C, 1990, SoPh.
Seismic Images of the Far Side and Interior of the Sun Lindsey, Seismic Images of the Far Side and Interior of the Sun Lindsey, C. & Braun, D.C, 2000, Science.C. & Braun, D.C, 2000, Science.
Pupil
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Helioseismic Imaging of the Helioseismic Imaging of the FarsideFarside
Phase of the Correlation
),,(),,(),,( tzHtzHdtzC rrr
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Improving the far-side monitorImproving the far-side monitor
FS00543
85 %
MDI (HMI)
GONG
Time Distance ( HMI + GONG)
Users able to subscribe to alerts > %
|B|
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Calibrating the far-side signalCalibrating the far-side signal
Carrington Longitude
sin
(lati
tud
e)
Active Region NOAA-10808
Aug 29 -> Sep 9 2005AR108
08
Active Region NOAA-10923
Oct 31 -> Nov 10 2006
AR10923
sin
(lati
tud
e)
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Calibrating the far-side signalCalibrating the far-side signal
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Calibrating the far-side signalCalibrating the far-side signal
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““far-side” imaging of the near far-side” imaging of the near sideside
1 x 3 skip method actually extends well onto the near side!
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Success rateSuccess rate
MDI
MDI
+
GONG
GONG
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Success RateSuccess Rate
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Why the improvement?Why the improvement?
Different length Different length of time seriesof time series
Duty CycleDuty Cycle Phase correctionPhase correction Bad dataBad data
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Why the improvement?Why the improvement? Phase CorrectionPhase Correction
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Why the improvement?Why the improvement? Mean Phase --> Temporal VariationMean Phase --> Temporal Variation
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Variation of the seismic solar Variation of the seismic solar radiusradius Solar acoustic radius variation --> solar cycle variationSolar acoustic radius variation --> solar cycle variation
Kholikov & Hill,
2008, SoPh
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Solar cycle variationSolar cycle variation Mean Phase --> Solar Cycle variation --> Solar acoustic Mean Phase --> Solar Cycle variation --> Solar acoustic
radius variation (??)radius variation (??)
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Solar cycle variationSolar cycle variation Mean Phase --> Solar Cycle variation --> Solar acoustic Mean Phase --> Solar Cycle variation --> Solar acoustic
radius variation--> Localized to surface magnetic areas (?)radius variation--> Localized to surface magnetic areas (?)
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Far-side maps from time-Far-side maps from time-distacedistace
GONG
MDI
September 03 2005
Courtesy of Junwei Zhao
Seismic holographyTime distance
NOAA 10808
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ArtifactsArtifacts Thomas Hartlep,Junwei Zhao Nagi N. Mansour, and Alexander G. Thomas Hartlep,Junwei Zhao Nagi N. Mansour, and Alexander G.
Kosovichev Kosovichev Validating Time-Distance Far-Side Imaging of Solar Validating Time-Distance Far-Side Imaging of Solar Active Regions through Numerical Simulations Active Regions through Numerical Simulations
ApJ, 689:1373–1378, 2008 December 20ApJ, 689:1373–1378, 2008 December 20
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Why the improvement?Why the improvement?GONG MDI
060902
060903
060902
060903
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Can we improve the Green’s Functions?
More realistic model --> Collaboration with Fernando Pérez at the IAC
Empirical calibration of the dispersion
Dispersion for several bounces
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Conclusions and Future workConclusions and Future work
MDI GONG
FS00543
85 %
Time Distance ( HMI + GONG)
Users able to subscribe to alerts > %
|B|
Improving the Maps
Calibration --> extending to the front side
Success Rate --> more accurate determination
Better Signal to Noise --> HMI data/ combination of ray paths / green’s functions / artifacts
Understanding Solar Cycle variations !!!