Farside Helioseismic Farside Helioseismic Holography: Recent Holography: Recent

AdvancesAdvances

I. González Hernández (1), D. Braun (2), S. M. Hanasoge(3), F. Hill (1),

C. Lindsey (2), P. Scherrer (3)

(1) National Solar Observatory, Tucson, AZ

(2) NorthWest Research Associates, Boulder, CO

(3) Stanford University, Stanford, CA

ContentsContents

Seismic imaging or Helioseismic Seismic imaging or Helioseismic holographyholography

Data: GONG near-real-time velocity imagesData: GONG near-real-time velocity images Prediction capability: NOAA-10808Prediction capability: NOAA-10808 Calibration of farside seismic holography Calibration of farside seismic holography

signalsignal CollaborationsCollaborations Conclusions and future workConclusions and future work

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, C. Seismic Images of the Far Side and Interior of the Sun Lindsey, C. & Braun, D.C, 2000, Science.& Braun, D.C, 2000, Science.

PtttzGdtdtzH ),(),,,,(),,( 2 rrrrr

Egression/Ingression

Pupil

Helioseismic Imaging of the Helioseismic Imaging of the FarsideFarside

Phase of the

Correlation

),,(),,(),,( tzHtzHdtzC rrr

Phase-difference due to:

Reduction of gas pressure in magnetic region displacement of density variation “Acoustic Wilson depression”

Sound speed enhancement (evidence from acoustic moats) due to thermal anomalies

Inclination of the magnetic field

GONG near-real-time dataGONG near-real-time data Continuous stream of velocity imagesContinuous stream of velocity images Quick calibration done at the sitesQuick calibration done at the sites 215x215 Gaussian-smoothed velocity images215x215 Gaussian-smoothed velocity images Transfer daily from six GONG stationsTransfer daily from six GONG stations Images merged in TucsonImages merged in Tucsonhttp://gong.nso.edu/quickreduce/quickpulse.html

Farside maps calculated from 1440-Farside maps calculated from 1440-min data series twice daily.min data series twice daily.Maps calculated approx. 12 hours Maps calculated approx. 12 hours after the last image has been taken.after the last image has been taken.Recalculated if the duty-cycle Recalculated if the duty-cycle increases due to extra transfer.increases due to extra transfer. Full-hemisphere farside maps.Full-hemisphere farside maps.http://soi.stanford.edu/farsidehttp://gong.nso.edu/data/farside

Prediction capabilityPrediction capability

Carrington Longitude

sin

(lati

tud

e)

Active Region NOAA-10808

Aug 29 Sep 9 2005 (GONG)

Sept 7 2005

AR10808

Source: MLSO K-coronameter

Magnetic calibrationMagnetic calibration

Analysis of particular cases.Analysis of particular cases. LocationLocation ClassificationClassification Evolution of magnetic regions/sunspotsEvolution of magnetic regions/sunspots

Frontside holography Frontside holography Relate phase-shifts Relate phase-shifts calculated by seismic imaging with calculated by seismic imaging with magnetic index on the visible sun.magnetic index on the visible sun.

Statistics, statistics:Statistics, statistics: GONG++ July 2001 GONG++ July 2001 present present

Use Artificial data to calibrate the effect on Use Artificial data to calibrate the effect on the farside signal of different anomaliesthe farside signal of different anomalies

Φ B

Calibrating the farside signalCalibrating the farside signal

Calibrating the farside signalCalibrating the farside signal

Source: www.solarmonitor.org

AreaArea(max)(max)

NSpotNSpotss(max)(max)

Hale/Hale/McIntoshMcIntosh

LocatioLocationn

FS FS regionregion

NOAA104NOAA1048484

17501750 6969 βγδβγδ / Ekc / Ekc N04W2N04W299

FS5700FS5700

NOAA104NOAA1048686

22002200 108108 βγδβγδ / Fkc / Fkc S17W63S17W63 FS5701FS5701

NOAA104NOAA1048787

280280 2323 ββ / Dao / Dao N12W2N12W222

NOAA104NOAA1048888

17501750 6161 βγδβγδ / Fkc / Fkc N08W6N08W699

FS5702FS5702

NOAA104NOAA1049595

220220 1616 ββ / Dso / Dso S22W48S22W48

NOAA105NOAA1050101

410410 2626 βγδβγδ / Dki / Dki N03W3N03W322

FS5703FS5703

NOAA105NOAA1051515

8080 99 ββ / Dso / Dso S02W01S02W01

NOAA105NOAA1051717

350350 1919 ββ / Dao / Dao S08W20S08W20

Calibrating the farside signalCalibrating the farside signal

Source: www.solarmonitor.org

AreaArea(max)(max)

NSpotNSpotss(max)(max)

Hale/Hale/McIntoshMcIntosh

LocatioLocationn

FS FS regionregion

NOAA104NOAA1048484

17501750 6969 βγδβγδ / Ekc / Ekc N04W2N04W299

FS5700FS5700

NOAA104NOAA1048686

22002200 108108 βγδβγδ / Fkc / Fkc S17W63S17W63 FS5701FS5701

NOAA104NOAA1048787

280280 2323 ββ / Dao / Dao N12W2N12W222

NOAA104NOAA1048888

17501750 6161 βγδβγδ / Fkc / Fkc N08W6N08W699

FS5702FS5702

NOAA104NOAA1049595

220220 1616 ββ / Dso / Dso S22W48S22W48

NOAA105NOAA1050101

410410 2626 βγδβγδ / Dki / Dki N03W3N03W322

FS5703FS5703

NOAA105NOAA1051515

8080 99 ββ / Dso / Dso S02W01S02W01

NOAA105NOAA1051717

350350 1919 ββ / Dao / Dao S08W20S08W20

Magnetic calibrationMagnetic calibration

Histograms of phase difference (from farside maps, left) and magnetic index (Kitt Peak magnetograms, right) versus latitude. The data used span from July 2001 to August 2003. The histograms in both cases seem to agree on the presence of more magnetic activity in the southern hemisphere for this period of time.

Magnetic CalibrationMagnetic Calibration

Scatter plots of phase-shifts from the synoptic maps constructed from farside calculated images  (Carrington Rotation 1996, left, and 2009, right) versus the square of the magnetic flux of the frontside synoptic maps from magnetograms (Kitt Peak)

Magnetic CalibrationMagnetic Calibration

Artificial data with simulated “sunspot”Artificial data with simulated “sunspot” Angular size: 25 –40 degreesAngular size: 25 –40 degrees Radial extend: 1MmRadial extend: 1Mm Sound speed perturbation: Increase ~10% on average.Sound speed perturbation: Increase ~10% on average.

• Bright green plage

• (?) faculae

• Dark red penumbra

• Bright red umbra

• Background blue quiet

• Light Blue faint

• Black network

• Dark green active network

Irradiance Variation

Courtesy of Juan Fontenla

Conclusions and future workConclusions and future work

MDI and GONG pipelines are providing daily full-MDI and GONG pipelines are providing daily full-hemisphere farside maps.hemisphere farside maps.

Large active regions are seen in consecutive Large active regions are seen in consecutive farside maps.farside maps.

Scientific Calibration Scientific Calibration Empirical calibration: Statistics with farside results Empirical calibration: Statistics with farside results

+frontside analysis+frontside analysis Calibration of artificial “sunspots”Calibration of artificial “sunspots” Calibrate effect of several bounces and dispersion Calibrate effect of several bounces and dispersion

relationrelation Ghost signature (?)Ghost signature (?)

Collaboration with irradiance variation studiesCollaboration with irradiance variation studies Continue refining the technique to improve its Continue refining the technique to improve its

capability as a space weather prediction toolcapability as a space weather prediction tool