Braun HMI/AIA Feb 2006 1 using helioseismology to probe magnetic structures (some selected topics)...

Braun HMI/AIA Feb 2006 1

using helioseismology to using helioseismology to probe magnetic structuresprobe magnetic structures

(some selected topics)(some selected topics)

NorthWest Research AssociatesNorthWest Research Associates

Colorado Research Associates DivisionColorado Research Associates Division

Doug Braun

NWRA / CoRA

2Braun HMI/AIA Feb 2006

Barry J. LaBonte Barry J. LaBonte


local helioseismology:local helioseismology:

Hankel analysisHankel analysis ring diagramsring diagrams time-distancetime-distance helioseismic helioseismic

holographyholography direct modelingdirect modeling

Gizon & Birch “Local Helioseismology” Gizon & Birch “Local Helioseismology” 20052005

Living Reviews in Solar Physics: Living Reviews in Solar Physics: livingreviews.orglivingreviews.org


selected topics:selected topics: far-side imaging of ARsfar-side imaging of ARs emerging ARSemerging ARS flows on AR-scalesflows on AR-scales seismic models of sunspotsseismic models of sunspots

what’s not herewhat’s not here excitation of waves by flares excitation of waves by flares magnetic (e.g. tachocline) influences on global magnetic (e.g. tachocline) influences on global

modesmodes lots of other thingslots of other things


I. far-side I. far-side imagingimaging

Lindsey & Braun 2000, Science 287, 1799

Braun & Lindsey 2001, ApJ, 560, L189

http://soi.stanford.edu/data/farside

2-skip + 1,3-skip implementation with MDI:

K. Osland and P. Scherrer


far-side imaging with far-side imaging with GONG:GONG:

http://gong.nso.edu/data/farside

see poster: González Hernández, et al.


II. (search for) subsurface II. (search for) subsurface emergence of magnetic fluxemergence of magnetic flux

Braun, D. 1995, Braun, D. 1995, PASP Conf. Series (GONG ‘94)PASP Conf. Series (GONG ‘94), 96, 250 , 96, 250 Chang, H.-K., et al. 1999, Chang, H.-K., et al. 1999, ApJApJ, 526, L53, 526, L53 Kosovichev, A., et al. 2000, Kosovichev, A., et al. 2000, Sol PhysSol Phys, 192, 159, 192, 159 Jensen, et al. 2001, Jensen, et al. 2001, ApJApJ, 553, L193 , 553, L193 Kosovichev, A. & Duvall, T. 2002, BAAS, 34, 791Kosovichev, A. & Duvall, T. 2002, BAAS, 34, 791

•results range from null, irreproducible (my own), to interesting and worth a second look

•none probe very deep, in the range where prediction might be practical (?)

•even without predictive capability, this pursuit is scientifically important


rising flux tube rising flux tube propertiesproperties

thin flux tube calculations (Fan & Gong 2000)

time

vr (rise speed)

two days before emergence:•depth z ~ 60 Mm•speed vr ~ 150 m/s•let diameter ~ fz (ff ≤ ≤ 11 !)•travel-time perturbation

120

fc

fzvr

•rms of single corr. ≥10 s

•can get N~100 correlations (maybe); error of mean ≥ 1s

•direct detection of vr (probably) unlikely, but…?

s

va


III. flows on AR scales (SEE III. flows on AR scales (SEE H8)H8)

ARs as divergent or convergent flows (e.g. Braun et al. 2004)

depth variation: shallow inflows and deeper outflows (e.g. Haber et al. 2004)

vertical vortiticy, kinetic helicity, other indices (e.g. Komm et al. 2005,

SEE POSTER #22)


AR flows with AR flows with time: AR9906time: AR9906

•flows not (simply) related to morphology changes

•complicated vorticity signatures


sunspots as:sunspots as:

Abdelatif, Lites & Thomas 1987, Abdelatif, Lites & Thomas 1987, ApJApJ, , 311, 1015311, 1015Abdelatif & Thomas 1987, Abdelatif & Thomas 1987, ApJApJ, 320, , 320, 884884

Braun, Duvall & LaBonte 1987, Braun, Duvall & LaBonte 1987, ApJApJ, , 319, L27319, L27

1988, 1988, ApJApJ, , 335, 1015335, 1015

absorbersabsorbers

refractorsrefractors


IV. seismic models of IV. seismic models of sunspotssunspots

models (forward & inverse) of sound-speed models (forward & inverse) of sound-speed variationsvariations e.g. Fan, et al. 1995; Kosovichev 1996; Chen et al. e.g. Fan, et al. 1995; Kosovichev 1996; Chen et al.

1998; Kosovichev, et al. 2000; Zhao & Kosovichev 1998; Kosovichev, et al. 2000; Zhao & Kosovichev 2003; Basu, et al. 2004; Couvidat et al. 2004, 2005; 2003; Basu, et al. 2004; Couvidat et al. 2004, 2005; Hughes, et al. 2005Hughes, et al. 2005

models of flowsmodels of flows e.g. Duvall, et al. 1996; Kosovichev 1996; Gizon et al. e.g. Duvall, et al. 1996; Kosovichev 1996; Gizon et al.

2000; Zhao et al. 2001; Zhao & Kosovichev 20032000; Zhao et al. 2001; Zhao & Kosovichev 2003 models of (other) magnetic effectsmodels of (other) magnetic effects: : complex complex

sound-speed, anisotropy,sound-speed, anisotropy, mode conversion, mode conversion, absorption, upper turning point depressions, etc.absorption, upper turning point depressions, etc. e.g. Chen, et al. 1997; Ryutova & Scherrer 1998; Cally, e.g. Chen, et al. 1997; Ryutova & Scherrer 1998; Cally,

et al. 2004; Crouch, et al. 2005; Lindsey & Braun 2005et al. 2004; Crouch, et al. 2005; Lindsey & Braun 2005


sunspot seismology: issuessunspot seismology: issues

keeping in mind that all models keeping in mind that all models are useful and important… are useful and important…

models with similar assumptions models with similar assumptions (e.g only sound-speed (e.g only sound-speed perturbations) often differ perturbations) often differ substantiallysubstantially

including realistic magnetic including realistic magnetic fields in stratified model is very fields in stratified model is very difficultdifficult

no current model is consistent no current model is consistent with (i.e. predicts) all with (i.e. predicts) all observations or known wave observations or known wave interactions in sunspotsinteractions in sunspots


1 vs 2-skip puzzle: Does 1 vs 2-skip puzzle: Does - + + = 2 ?

Braun (1997):Braun (1997): No No (for (for > 150Mm ) > 150Mm )

Zhao & Kosovichev Zhao & Kosovichev (2006): (2006): Yes Yes (for (for =24 – 73 Mm ) =24 – 73 Mm )

Braun (2006): Braun (2006): No No (for (for =35 – 110 Mm ) =35 – 110 Mm )

- : incoming travel-time (center-annulus or ingression-control)

2/2 : (half the) double-skip travel-time (annulus-annulus or

egression-ingression)

+ : “outgoing travel-time (center-annulus or egression-control)

Δ

Δ


absorption: mode absorption: mode conversion?conversion?

slow modes:

Spruit & Bogdan

Cally & Bogdan (1997)

Crouch, et al. (2005)

SEE POSTER #17

Hankel analysis :

phase shiftsabsorption

Holography: :

normalized egression power


Schunker, Braun, Cally, & Lindsey 2005 “Local Helioseismology of Inclined Magnetic Fields and the Showerglass Effect,” ApJ 621, L149

Goal: look for evidence of the conversion of vertically oscillating p-modes to elliptical motion in inclined fields in sunspot penumbrae.

Observations: MDI (SOHO) - helioseismic

IVM (Mees Obs.) – Stokes Method: measure correlation between ingression and direct velocity signal at different projected l.o.s angles (p) in plane of magnetic field.

AR 9026


evidence for elliptical motion (mode evidence for elliptical motion (mode conversion)conversion)

phase modulus

θp

•varies with field strength/inclination

•observed throughout 3-5mHz frequency range

•measured in several spots

•observed in TD measurements (Zhao & Kosovichev 2006)

•not predicted for, or observed in, scalar quantities (e.g. intensity)

projected line-of-sight angle (from vertical)

inner penumbra

middle penumbra

outer penumbra.


challenges:challenges: farside:farside:

how can we calibrate it?how can we calibrate it? how can we improve it?how can we improve it?

emerging ARs:emerging ARs: can we detect direct or indirect effects (e.g. horizontal flows)?can we detect direct or indirect effects (e.g. horizontal flows)? can theories & simulations tell us what to look for?can theories & simulations tell us what to look for?

flows: flows: how do we combine surface (Doppler, feature-tracking) and how do we combine surface (Doppler, feature-tracking) and

subsurface information?subsurface information? what spatial, temporal scales, products, indices are useful and what spatial, temporal scales, products, indices are useful and

help solve physical problems?help solve physical problems? sunspots:sunspots:

how do we exploit all of the observations (1,2-skip, frequency how do we exploit all of the observations (1,2-skip, frequency variations, lines-of-sight angles, absorption, etc)variations, lines-of-sight angles, absorption, etc)

how do we include explicit magnetic effects in forward (and how do we include explicit magnetic effects in forward (and inverse) models?inverse) models?

how can MHD simulations help?how can MHD simulations help?


further information:further information:

http://cora.nwra.com/~dbraun

NASA (LWS and SR&T programs)

NSF (Stellar Astronomy and Astrophysics program)

supporsupport:t:

Braun HMI/AIA Feb 2006 1 using helioseismology to probe magnetic structures (some selected topics)...

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