SP-624October 2006

SOHO 18/GONG 2006/HELAS IBeyond the spherical Sun

7-11 August 2006Sheffield, UK

Scientific Organising Committee

Michael Thompson (Chair) University of Sheffield, UKBo Andersen Norwegian Space Centre, NorwayAnnie Baglin Observatoire de Paris-Meudon, FranceSarbani Basu Yale University, USAPaul Cally Monash University, AustraliaYvonne Elsworth University of Birmingham, UKBernhard Fleck ESA Space Science Department, USADouglas Gough University of Cambridge, UKHans Kjeldsen Aarhus University, DenmarkDon Kurtz University of Central Lancashire, UKJohn Leibacher National Solar Observatory, USAPere Pallé Instituto de Astrofisica de Canarias, SpainPhil Scherrer Stanford University, USAHiromoto Shibahashi University of Tokyo, JapanSylvaine Turck-Chièze Service d’Astrophysique / DAPNIA, France

Local Organising Committee

Michael Thompson (Chair) University of SheffieldRobert Erdélyi University of SheffieldRekha Jain University of SheffieldRoger New Sheffield Hallam University

Publication: Proceedings, SOHO 18/GONG 2006/HELAS IBeyond the spherical SunNoordwijk, The Netherlands(ESA SP-624, October 2006)

Editor: Karen Fletcher

Scientific Editor: Michael Thompson

Published and distributed by: ESA Publications DivisionESTECPostbus 2992200 AG NoordwijkThe NetherlandsTel: +31 71 565 3400Fax: +31 71 565 5433

Printed in: The Netherlands

Price: 60

ISBN: 92-9092-935-9

ISSN: 0379-6566

Copyright: © 2006 European Space Agency

CONTENTS

Introduction and welcomeChair: B Fleck

Various dynamical puzzle pieces in the seismic Rubik’s cubeJ Toomre

Session 1

Local methodologiesChair: B Fleck

Local helioseismology: techniques and issuesA C Birch

Farside helioseismic holography: recent advancesI González Hernández, F Hill, C Lindsey, D Braun, P Scherrer, S M Hanasoge

Magnetoseismic signatures of active regions and the question of rapid downflows beneath sunspotsC Lindsey

Observed and simulated photospheric velocities within inclined magnetic fieldsH Schunker, P Cally

Session 2

Temporal variations and flowsChair: M Roth

Seismic results on temporal variation of the solar interiorR Howe

Toward improving the seismic visibility of the solar tachoclineS M Jefferies, S V Vorontsov, C Giebink

The seismic Sun over three activity cyclesW J Chaplin, Y Elsworth, S J Hale, B A Miller, G A Verner, R New

Cyclic variability of the seismic solar radius from SOHO/MDI and related physicsS Lefebvre, A G Kosovichev, P Nghiem, S Turck-Chièze, and J P Rozelot

Interior structures and flows beneath sunspots from time-distance helioseismologyJ Zhao

Subsurface convective flows within active regionsB W Hindman, D A Haber, J Toomre

Session 2 (continued)

Chair: P Cally

Consequences of large-scale flows around active regions on the dispersal of magnetic field across thesolar surfaceM L DeRosa, C J Schrijver

Effect of the subsurface shear layer on solar supergranulationC A Green, A G Kosovichev, M S Miesch

Effect of sunspot structure from p-modes scatteringM Gordovskyy, R Jain, M J Thompson

Session 3

Seismology above the photosphereChair: P Cally

Magnetic seismology of the lower solar atmosphereR Erdélyi

Low-frequency magneto-acoustic waves in the solar chromosphereS M Jefferies, S W McIntosh, J D Armstrong, T J Bogdan, A Cacciani, B Fleck

Session 4

Modelling the solar interiorChair: R Komm

Reconciling the revised solar abundances with helioseismic constraintsJ A Guzik

Non-kinematic flux-transport dynamos and torsional oscillationsM Rempel

Solar evolution model with diffusion and new equation of stateS V Ayukov, V A Baturin, A B Gorshkov

Molecular-dynamics simulations of hot dense Coulomb systemsK Mussack, D Mao, W Däppen

Session 5

Low-degree seismology from the Sun to the starsChair: D O Gough

Helioseismology with low-degree observations: where we stand, and what the future holdsW J Chaplin

The internal structure of the Sun inferred from g modes and low-frequency p modesY P Elsworth et al.

Detection of periodic signatures in the solar power spectrum On the track of l=1 gravity modesR A García, S Turck-Chièze, S J Jiménez-Reyes, J Ballot, P L Pallé, A Eff-Darwich, S Mathur, J Provost

The DynaMICS perspectiveS Turck-Chièze et al.

Observations of solar-like oscillationsT Bedding, H Kjeldsen

Rigorous analysis of dipolar oscillations of starsM Takata

Frequency, splitting, linewidth and amplitude estimates of low-l p modes of alpha Cen A: analysis ofWIRE photometryS T Fletcher, W J Chaplin, Y Elsworth, J Schou, D Buzasi

Session 6

Mode physicsChair: H Kjeldsen

Stochastic excitation and damping of solar-like oscillationsG Houdek

Energetic effects in classical pulsatorsM-A Dupret, A Grigahcène, S Théado, P-O Bourge, M Gabriel

Session 7

A new era of asteroseismlogyChair: H Kjeldsen

Studying solar-like oscillations in red giants: MOST spacebased photometry of epsilon OphiuchiC Barban et al.

Modelling intermediate mass red giantsO Moreira, A Noels, M-A Dupret

Session 7 (continued)

Chair: S Basu

Asteroseismology of hot B subdwarf stars: a brief overviewG Fontaine, P Brassard, S Charpinet, E M Green, P Chayer, S Randall, B Dorman

Observations of magneto-acoustic modes in strongly magnetic pulsating roAp starsD W Kurtz, V G Elkin, G Mathys

The seismology programme of the CoRoT space missionA Baglin, E Michel, M Auvergne, and the CoRoT team

Session 8

Dynamics and numerical simulationChair: F Hill

Asteroseismology of exoplanets-host starsS Vauclair

Dynamical processes in stellar radiation zones: secular magnetohydrodynamics of rotating starsS Mathis, T Decressin, A Palacios, L Siess, C Charbonnel, S Turck-Chièze, J-P Zahn

Internal gravity waves in the SunS Talon

Dynamical processes in the solar radiative interiorA Palacios, S Talon, S Turck-Chièze, C Charbonnel

Suppression of amplitude of 5-min oscillations in sunspots due to the lack of acoustic sourcesK Parchevsky, A Kosovichev

Solar acoustic simulatorS M Hanasoge, T L Duvall

Prospects for helio- and asteroseismologyJ Christensen-Dalsgaard

Poster Papers

P1 Optimal phase-speed filters in time-distance helioseismology

S Couvidat, A C Birch

P2 Sensitivity kernels for helioseismic travel times in spherical geometry – preliminary results

M Roth, L Gizon, A C Birch

P3 Acoustic scattering by flux tubes: is the Born approximation valid?

L Gizon, S M Hanasoge, A C Birch

P4 Large-scale circulations using ring analysis

D Haber, B Hindman, J Toomre, R S Bogart

P6 The group velocity of solar p modes

S V Vorontsov

P8 Temporal variations of travel-time differences from GONG++

S Kholikov, J Leibacher

P10 Correcting Dopplergrams for solar active regions: consequences for local helioseismology

R Wachter, S P Rajaguru, R S Bogart

P11 Effects of horizontal magnetic fields on acoustic travel-times

R Jain

P12 Dynamics study of solar oscillations and granulation with THÉMIS observations

R Simoniello, S J Jiménez Reyes

P13 Inferring subsurface supergranular flow directly from helioseismic correlation data

M F Woodard

P14 f-mode sensitivity kernels for flows

J Jackiewicz, L Gizon, A Birch

P15 Subsurface flows measured with big rings

R Komm, I González Hernández, R Howe, F Hill

P16 Subsurface flows from numerical simulations compared with flows from ring analysis

S Ustyugov, R Komm, O Burtseva, R Howe, S Kholikov

P18 B0-angle effect on zonal and meridional flow determinations from 3 years ring diagram analysis of

GONG++ data

A Zaatri, R Komm, I González Hernández, R Howe, T Corbard

P22 Solar rotation and zonal flows from Mount Wilson 60 ft tower data

R Howe, R Bogart, J Christensen-Dalsgaard, E J Rhodes Jr, P Rose, J Schou

P23 Meridional flow measurements with statistical waveform analysis

U Mitra-Kraev, M J Thompson, M F Woodard

P24 Examining possible errors in the inversion results of active regions through a model study

C-H Lin, L Li, S Basu

P25 Acoustic power and magnetic field orientation in a large sunspot

S Gosain, P Venkatakrishnan, K Venugopalan

P26 The cookie cutter test for time-distance tomography of active regions

S G Korzennik

P27 Comparative study of isolated sunspots using time-distance helioseismology

S Zharkov, C J Nicholas, M J Thompson

P28 Subsurface structure evolution associated with the rise and fall of intensely active regions

R S Bogart, S Basu, M C Rabello-Soares, H M Antia

P29 Three-dimensional numerical simulation of wave propagation through a model sunspot

R Cameron, L Gizon

P30 Magnetic field inclination and atmospheric oscillations above solar active regions: theory

P S Cally, H Schunker

P31 On the enhanced velocity oscillations observed during solar flares

B Kumar, P Venkatakrishnan, K Venugopalan

P33 The acoustically active solar flare of 2005 January 15

H Moradi, A-C Donea, C Lindsey, D Besliu-Ionescu, P S Cally

P34 Seismic emission from M-class solar flares

D Besliu-Ionescu, A-C Donea, P Cally, C Lindsey

P35 Peak parameter shifts from large-aperture ring diagram analysis

R Howe, I González Hernández, F Hill, R Komm

P36 Phenomenological simulation of the total solar irradiance and its power spectrum

H Vázquez Ramió, C Régulo, T Roca Cortés

P37 Solar mean magnetic field near the surface and its variation during a cycle

P A P Nghiem, R A García, S J Jiménez-Reyes

P38 High-degree mode frequencies: changes with solar cycle

M C Rabello-Soares, S G Korzennik, J Schou

P39 Helioseismic modes in a magnetic atmospheric solar model

B Pintér, R Erdélyi

P40 Hydrodynamic evolution of the solar tachocline

S Talon

P41 How magnetic is the solar tachocline?

R Arlt, A Sule, G Rüdiger

P42 MHD turbulence on a ß-plane

N Leprovost, E-J Kim

P43 Turbulent transport in the solar interior

E-J Kim, N Leprovost

P44 Convection and non-axisymmetric large-scale flows at the base of the solar convection zone

E Tikhomolov

P45 A non-local MLT treatment fitting 3D simulations

M-A Dupret, M-J Goupil, R Samadi, A Grigahcène, M Gabriel

P46 Supergranule scale convection simulations

R F Stein, D Benson, D Georgobiani, Å Nordlund

P47 Seismic estimate of solar heavy element abundances

S Basu, H M Antia

P48 A seismic solar model with the updated elemental abundances

H Shibahashi, S Tamura

P49 Rotation inversions of artificial solarFLAG Sun-as-a-star data

W J Chaplin et al.

P50 Coupling of high-degree solar p modes by differential rotation

S V Vorontsov

P51 On the direct determination of sensitivity, resolution and information content of helioseismic data

– application to the inversion of the solar core rotation rate

A Eff-Darwich, S G Korzennik, S J Jiménez-Reyes, R A García

P52 Evolutionary convective envelope in modern model of the Sun

V A Baturin

P53 A new method to estimate the acoustic cut-off frequency of the Sun using the different properties

between p-modes and pseudomodes of low degree

A Jiménez, S J Jiménez-Reyes, R A García

P54 Examining the effect of the new chemical composition on solar structure by using the adiabatic

index

C-H Lin, H M Antia, S Basu

P55 On seismic signatures of rapid variation

G Houdek, D O Gough

P56 How GOLF sees the second helium ionization layer across the solar cycle

J Ballot, S J Jiménez-Reyes, R A García

P57 Solar-cycle variations in p-mode frequencies and even-order splitting coefficients from LOWL

observations

D Salabert, S J Jiménez-Reyes

P58 Are the shapes of the p-mode peaks ‘distorted’ by the solar cycle when they are observed in long,

multi-year power frequency spectra?

W J Chaplin, Y Elsworth, R New, T Toutain

P59 How does the change on solar abundances affect low degree modes?

A Zaatri, J Provost, G Berthomieu, P Morel, T Corbard

P61 Changes to global mode parameters over a solar cycle

S C Tripathy, F Hill, K Jain, J W Leibacher

P62 Comparison of the solar velocity spectrum from MDI and GOLF during cycle 23

S Lefebvre, R A García, S J Jiménez-Reyes, S Turck-Chièze

P63 Sensitivity of the predicted frequencies of l = 1 gravity modes to known physical processes

S Mathur, S Turck-Chièze, S Couvidat, R A Garcia

P64 Needles in haystacks: how to use contemporaneous data in the search for g-modes

A M Broomhall, W J Chaplin, Y Elsworth

P65 Theoretical damping rates and phase-lags for solar-like oscillations

M A Dupret, C Barban, M-J Goupil, R Samadi, A Grigahcène, M Gabriel

P66 Solar-activity changes in the p-mode damping and excitation observed in LOWL data

D Salabert, S J Jiménez-Reyes

P68 BiSON update

J Allison et al.

P69 Analysis of velocity-noise variations arising from photon-noise in data from the GOLF instrument

R New, W J Chaplin, Y P Elsworth, R A García, S J Jiménez-Reyes

P70 Reliable analysis of power and phase features as seen from BiSON and GOLF observations

R Simoniello, Y P Elsworth, W J Chaplin, R García

P71 Comparison of solar p-mode lifetimes from GONG, MDI and TON data

O Burtseva, S Kholikov, F Hill, J Bolding, O Ladenkov, D-Y Chou

P72 A comparison of acoustic mode parameters using multi-spectral data

K Jain et al.

P73 Comparison of local frequency shifts between MDI velocity and intensity data

S C Tripathy, H M Antia, F Hill, K Jain, I González Hernández et al.

P75 High resolution spectrum: towards a new observational strategy

N Seghouani

P76 Study of the role of phase evolution in the amplitudes of low-degree solar p-modes

R Simoniello, W J Chaplin, Y Elsworth, R New

P78 The effects of rotation on frequency of stellar oscillations

K D Burke, M J Thompson

P79 On the possible existence of localised vacillating convection state in rapidly rotating young solar-

like stars

J Ballot, A S Brun, S Turck-Chièze

P80 Asteroseismic diagnostics of stellar convective cores

A Mazumdar, S Basu, B L Collier, P Demarque

P81 Kepler telescope and solar-like pulsators

J Molenda-Zakowicz, T Arentoft, H Kjeldsen, A Bonanno

P82 Calibrating the solar dynamo: magnetic activity cycles of southern Sun-like stars

T S Metcalfe, T J Henry, M Knölker, D R Soderblom

P83 On the prospects for sounding activity cycles on Sun-like stars

W J Chaplin, Y Elsworth, G Houdek, R New

P84 Evidence for degree dependence of changes in p-mode damping along the solar cycle in Sun-as-a-

star data

D Salabert, W J Chaplin, Y Elsworth, R New, G A Verner

P85 The complementary roles of interferometry and asteroseismology

O L Creevey, M J P F G Monteiro, T S Metcalfe, T M Brown

P86 12 Bootis: the need for asteroseismic constraints

A Miglio, J Montalbán, C Maceroni, J De Ridder, F D’Antona

P87 Procyon-A and Bootis: observational frequencies analyzed by the local-wave formalism

P A P Nghiem, J Ballot, R A García, P Lambert, S Turck-Chièze

P89 A line profile analysis of the pulsating red giant star Ophiuchi (G9.5III)

S Hekker, C Aerts, J De Ridder, F Carrier

P90 Asteroseismology of K giants

M P Di Mauro et al.

P91 Pulsational properties of the Cephei star SY Equ from combined photometric and spectroscopic

observations

J Daszynska-Daszkiewicz, A Pigulski

P92 Chemical composition of the pulsating Cephei star Peg

E Niemczura, G Polubek

P93 SIAMOIS: an asteroseismic network with 1 site… in Antarctica

M Benoît and the SIAMOIS team

P95 The spectral resolving power of irregularly sampled time series

F Pijpers

P97 Helioseismology of sub-photospheric flows

S Shelyag, R Erdélyi, M J Thompson

P101 Forward modeling of atmospheric magneto-acoustic-gravity waves

J D Armstrong

P102 The parameters of seismic sources in the flare of 28 October 2003

V V Zharkova, S I Zharkov

P103 g-mode search and the solar cycle

A Gabriel

P104 Does the inference of solar subsurface flow change with choice of the spectral line?

K Jain, F Hill, I González Hernández, C G Toner, S C Tripathy, J D Armstrong, S M Jefferies

P105 Temporal variations of solar rotation during solar cycle 23

S Basu, H M Antia

P106 Time-varying component of the solar meridional flow

L Gizon, M Rempel

P109 European helio- and asteroseismology network – HELAS

M Roth et al.

P110 Propagation of p-modes into the solar atmosphere*

Y Taroyan, R Erdélyi, C Malins

* Please note this paper is not listed in the contents of the Proceedings, but the paper is present on the CD.

Late papers

The pulsations and potential for seismology of B starsC Aerts

Distribution of MDI p-mode power correlation coefficientsH Y Chang, T Sekii

Helioseismic probing of giant-cell convectionN A Featherstone, D A Haber, B W Hindman, J Toomre

Sunquake sources and wave propagationA G Kosovichev