Holography & HMI NorthWest Research Associates, Inc. Colorado Research Associates Division D. Braun, C. Lindsey, A. Birch (NWRA/CoRA) collaborators: P. Cally, A. Donea, H. Schunker (Monash U.), J. Werne, M. Woodard (NWRA/CoRA)

HMI Science goals for holography farside imaging –space weather prediction –AR evolution flows –physics of solar convection –magnetic flux transport and emergence active regions –structure and evolution of ARs flares –physics of flares – flare as point-source for local helioseismology

H - = ingressionH + = egression helioseismic holography

acoustic power holography egression,ingression: (space-time domain) egression,ingression power: sensitive to sources, sinks at focus (z = depth,r = horizontal position,  = surface amplitude, G ± = Greens’ functions)

Seismic images of a solar flare X July 7 (AR 7978) propagating waves (Kosovichev & Zharkova 1998, Nature, 393, 317) acoustic power holography to image source (Donea, Braun & Lindsey 1999, ApJ, 513, L146) only acoustic flare signature until…

2003 Oct 28, X17 flare (AR 486) A. Donea (Monash U.) & C. Lindsey (NWRA) 11:00 UT 11:10 UT 11:25 UT “instantaneous” egression power between 5-7 mHz computed in subjacent vantage with focus at surface. 100 Mm

phase-correlation holography egression, ingression: correlation: travel-time perturbation: correlation phase: (space-frequency domain) sensitive to refractive perturbations at focus

farside imaging Braun & Lindsey (2001, ApJ, 560, L189)

AR 486 first appeared on farside ARs 486,488 on farside 2003 Oct Oct Oct Nov 12

phase-sensitive holography of flows egressions and ingressions in 4 quadrants: e.g. E-W correlation phase: velocity: WE N S

1999 April 20, focus = 3 Mm

supergranulation and moat flows

holographic flow kernels (A. Birch)

supergranular depth sensitivity v  e -z/z o cos(  z/z 1 ) z o =2.5 Mm. red crosses : no return flow (z 1  ). green circles: z 1 = 5 Mm black diamonds: z 1 = 15 Mm. div v h pupil (Braun, Birch, & Lindsey 2004 SOHO/GONG Proceedings)

horizontal divergence (smeared to 7.5°)

vertical vorticity (smeared to 7.5°) vort v h = (1/cosB)  ( cosB v B ) /  L – (1/cosB)  v L /  B

vorticity and rotation rate near ARs slight association of ARs with positive vertical vorticity sunspots tend to occur near the boundaries of regions of opposite zonal shear: – excess rotation rate in ARs N hemisph. S hemisph. (Braun, Birch, & Lindsey 2004 SOHO/GONG Proceedings)

time and longitude-averaged flows

probing the tachocline

the showerglass effect

showerglass assessment: local control correlations  = local acoustic amplitude quiet Sun: control (expect C ± = 1) magnetic region: C - describes how surface fields shift phase and amplitude of local photospheric signature of incoming waves C + describes influence of field on outgoing waves

Lindsey C. & Braun, D.C “The Acoustic Showerglass I. Seismic Diagnostics of Photoshperic Magnetic Fields,” ApJ (in press) -“The Acoustic Showerglass II. Imaging Active Region Subphotospheres,” ApJ (in press)

application of showerglass correction focus = 4.2 Mm 5.6 Mm 7.0 Mm 8.4 Mm 9.7 Mm uncorrected corrected |  c| < 250 m/s

focus depth = 3 Mm 5 Mm 7 Mm no correction showerglass corrected application of showerglass correction to horizonal-flow signatures

Schunker, Braun, Cally, & Lindsey 2005 “Local Helioseismology of Inclined Magnetic Fields and the Showerglass Effect,” ApJL submitted

HMI tasks for holography farside imaging –upgrades, software rewrites –investigate high-  egression power maps for near-limb ARs flows –f-mode holography for near surface –forward and inverse modeling –adaption of farside codes to deep interior active regions –understand showerglass effects (surface phase and amplitude distortions) for correcting subsurface signatures flares –diagnostics of seismic flare emission (why relatively rare?) artificial data for testing local helioseismology