Sub-surface evolution of AR 0486, AR 0069, and AR 9906, from GONG++ data R. Komm, R. Howe, F. Hill, I. Gonz´ alez Hern ´ andez, and C. Toner National Solar Observatory, Tucson, AZ Introduction y We study the subsurface evolution of the flows near active regions AR 0486, AR 0069, and AR 9906 during their disk passage. We use a local helioseismology technique, ring- diagram analysis, to determine the flows in the upper 16 Mm of the convection zone from high-resolution GONG data. Since the current analysis is limited to regions within 60 o of heliographic latitude and central meridian distance, we cannot measure flows near the solar limb associated with the active regions that spawned the events on Apr 21 and Aug 24, 2002. We use kinetic helicity density as a measure of the complexity of the subsurface flows associated with these 3 active regions. AR 0486 (Oct 25 – Nov 1, 2003) 031029 X10 GONG data GOES data Left: Intensity, modulation, and magnetic field strength at the peak of the flare event (top); same images after subtracting a reference frame (2nd); temporal variation at 3 locations indicated by colored crosses (bottom). Right: Number of X-ray flares and their intensity as a function of dense-pack days. y The scalar product of velocity and vorticity vector, the kinetic helicity density (Moffatt & Tsinober, 1992), shows significant values near the location of AR 0486 (–22.5 o to –15 o ). The temporal variation of the kinetic helicity density with depth for 9 dense-pack regions and their signal-to-error ratios. The regions that sample AR 0486 (–22.5 o , –15 o latitude; 285 o longitude) show large values with systematic variations. References y Haber D.A., Hindman, B.W., Toomre, J., Bogart, R.S., Larsen, R.M., & Hill, F. 2002, ApJ, 570, 885 Komm, R., Corbard, T., Durney, B.R., Gonz´ alez Hern ´ andez, I., Hill, F., Howe, R., & Toner, C. 2004, ApJ, 605, 554 Moffatt, H.K. & Tsinober, A. 1992, Annu. Rev. Fluid Mech., 24, 281 Solar X-ray Flares from the GOES satellite (http://www.ngdc.noaa.gov) Dense-Pack Ring-Diagram Analysis Slices in ( ) Slice in ( ) Each region is tracked using a surface rotation rate. A 2-dim cut of the power spectrum at a given temporal frequency shows a set of rings shifted by the horizontal flow field. These shifts are inverted to derive velocities with depth (Haber et al. 2002). AR 0069 (Aug 13 – 21, 2002) Left: Spatial distribution of X-ray flares by flare class (C: cross; M: square; X: diamond) and dense-pack regions (grid points; circle). Right: Number of X-ray flares and their intensity (GOES data) as a function of dense-pack days (1664 min). y The kinetic helicity density shows significant values near the location of AR 0069 (–15 o to –7.5 o ). The sign changes with depth distinguishing 3 ranges (similar to AR 0486 to the left). Same as figure to the left. The regions that include AR 0069 and the flare locations (–15 o , –7.5 o lat; 300 o long and –7.5 o lat ; 307.5 o long ) show large values and systematic variations. The large flares occur near the end of the time period. Acknowledgments This work was supported by NASA grant NAG 5-11703. This work utilizes data obtained by the Global Oscillation Network Group (GONG) program, managed by the National Solar Observatory, which is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation. The data were acquired by instruments operated by the Big Bear Solar Observatory, High Altitude Observatory, Learmonth Solar Observatory, Udaipur Solar Observatory, Instituto de Astrof´ ısica de Canarias, and Cerro Tololo Interamerican Observatory. NSO/Kitt Peak data used here are produced cooperatively by NSF/NOAO, NASA/GSFC, and NOAA/SEL. Summary y The subsurface flows associated with AR 0486 and AR 0069 show significant helicity values. A change in sign separates 3 depth ranges. The temporal variation of kinetic helicity is large and systematic for AR 0486 and AR 0069 at dense-pack regions that include locations of flare activity. The subsurface flows associated with AR 9906 show small helicity values but a “dipolar” structure in the zonal vorticity. The X10 flare on Oct 29, 2003 in AR 0486 was observed by GONG in intensity, modulation, and magnetic field strength. AR 9906 (Apr 10 – 18, 2002) Same as figure to the left for AR 9906. Compared with AR 0486 and AR 0069, there is hardly any flare activity during the disk passage of AR 9906. (AR 9906 is too close to the limb on Apr 21, 2002 for a ring-diagram analysis.) y The kinetic helicity density values associated with AR 9906 are much smaller compared to the values of the other two regions and are hardly significant. Same as figure to the left for AR 9906. Not much going on under AR 9906 during its disk passage. However, AR 9906 shows a “dipolar” structure in the zonal vorticity component, a signature of flare-producing regions. The ring-fitting analysis is based on algorithms developed by Haber, Hindman, and Larsen with support from NASA and Stanford University. This poster was prepared with Hardi Peter’s LaTex package.
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Sub-surface evolution of AR 0486, AR 0069, and AR 9906, from GONG++ dataR. Komm, R. Howe, F. Hill, I. Gonzalez Hernandez, and C. Toner
National Solar Observatory, Tucson, AZ
Introduction y
We study the subsurface evolution of the flows near activeregions AR 0486, AR 0069, and AR 9906 during their diskpassage. We use a local helioseismology technique, ring-diagram analysis, to determine the flows in the upper 16Mm of the convection zone from high-resolution GONG data.Since the current analysis is limited to regions within 60o ofheliographic latitude and central meridian distance, we cannotmeasure flows near the solar limb associated with the activeregions that spawned the events on Apr 21 and Aug 24, 2002.We use kinetic helicity density as a measure of the complexityof the subsurface flows associated with these 3 active regions.
AR 0486 (Oct 25 – Nov 1, 2003)031029 X10 GONG data
GOES data
Left: Intensity, modulation, and magnetic field strength at thepeak of the flare event (top); same images after subtractinga reference frame (2nd); temporal variation at 3 locationsindicated by colored crosses (bottom). Right: Number of X-rayflares and their intensity as a function of dense-pack days. y
The scalar product of velocity and vorticity vector, the kinetichelicity density (Moffatt & Tsinober, 1992), shows significantvalues near the location of AR 0486 (–22.5o to –15o).
The temporal variation of the kinetic helicity density with depthfor 9 dense-pack regions and their signal-to-error ratios. Theregions that sample AR 0486 (–22.5o, –15o latitude; 285o
longitude) show large values with systematic variations.
References y
Haber D.A., Hindman, B.W., Toomre, J., Bogart, R.S., Larsen, R.M., &Hill, F. 2002, ApJ, 570, 885
Komm, R., Corbard, T., Durney, B.R., Gonzalez Hernandez, I., Hill, F.,Howe, R., & Toner, C. 2004, ApJ, 605, 554
Moffatt, H.K. & Tsinober, A. 1992, Annu. Rev. Fluid Mech., 24, 281Solar X-ray Flares from the GOES satellite (http://www.ngdc.noaa.gov)
Dense-Pack Ring-Diagram Analysis
Slices in (��� ��) Slice in (�� �)
Each region is tracked using a surface rotation rate. A 2-dim cutof the power spectrum at a given temporal frequency shows aset of rings shifted by the horizontal flow field. These shifts areinverted to derive velocities with depth (Haber et al. 2002).
AR 0069 (Aug 13 – 21, 2002)
Left: Spatial distribution of X-ray flares by flare class (C: cross;M: square; X: diamond) and dense-pack regions (grid points;circle). Right: Number of X-ray flares and their intensity (GOESdata) as a function of dense-pack days (1664 min). y
The kinetic helicity density shows significant values near thelocation of AR 0069 (–15o to –7.5o). The sign changes withdepth distinguishing 3 ranges (similar to AR 0486 to the left).
Same as figure to the left. The regions that include AR 0069and the flare locations (–15o, –7.5o lat; 300o long and –7.5o lat ;307.5o long ) show large values and systematic variations. Thelarge flares occur near the end of the time period.
Acknowledgments
This work was supported by NASA grant NAG 5-11703. This work utilizes dataobtained by the Global Oscillation Network Group (GONG) program, managed bythe National Solar Observatory, which is operated by AURA, Inc. under a cooperativeagreement with the National Science Foundation. The data were acquired byinstruments operated by the Big Bear Solar Observatory, High Altitude Observatory,Learmonth Solar Observatory, Udaipur Solar Observatory, Instituto de Astrofısicade Canarias, and Cerro Tololo Interamerican Observatory. NSO/Kitt Peak data usedhere are produced cooperatively by NSF/NOAO, NASA/GSFC, and NOAA/SEL.
Summary y
The subsurface flows associated with AR 0486 and AR 0069show significant helicity values. A change in sign separates 3depth ranges.
The temporal variation of kinetic helicity is large and systematicfor AR 0486 and AR 0069 at dense-pack regions that includelocations of flare activity.
The subsurface flows associated with AR 9906 show smallhelicity values but a “dipolar” structure in the zonal vorticity.
The X10 flare on Oct 29, 2003 in AR 0486 was observed byGONG in intensity, modulation, and magnetic field strength.
AR 9906 (Apr 10 – 18, 2002)
Same as figure to the left for AR 9906. Compared with AR 0486and AR 0069, there is hardly any flare activity during the diskpassage of AR 9906. (AR 9906 is too close to the limb on Apr21, 2002 for a ring-diagram analysis.) y
The kinetic helicity density values associated with AR 9906 aremuch smaller compared to the values of the other two regionsand are hardly significant.
Same as figure to the left for AR 9906. Not much going onunder AR 9906 during its disk passage. However, AR 9906shows a “dipolar” structure in the zonal vorticity component, asignature of flare-producing regions.
The ring-fitting analysis is based on algorithms developed by Haber, Hindman, andLarsen with support from NASA and Stanford University. This poster was preparedwith Hardi Peter’s LaTex package.
Related Documents
