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Dynamics of the photosphere along the solar cycle from SDO/HMI

Roudier, Th., Malherbe, J. M. and Mirouh, G. M. (2017) Dynamics of the photosphere along the solar cycle from SDO/HMI Astronomy & Astrophysics, 598, A99.

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<p><b>Context.<b> As the global magnetic field of the Sun has an activity cycle, one expects to observe some variation of the dynamical properties of the flows visible in the photosphere.<p> <p><b>Aims.<b> We investigate the flow field during the solar cycle by analysing SDO/HMI observations of continuum intensity, Doppler velocity and longitudinal magnetic field.<p> <p><b>Methods.<b> We first picked data at disk center during 6 yr along the solar cycle with a 48-h time step in order to study the overall evolution of the continuum intensity and magnetic field. Then we focused on thirty 6-h sequences of quiet regions without any remnant of magnetic activity separated by 6 months, in summer and winter, when disk center latitude B0 is close to zero. The horizontal velocity was derived from the local correlation tracking technique over a field of view of 216.4 Mm × 216.4 Mm located at disk center.<p> <p><b>Results.<b> Our measurements at disk center show the stability of the flow properties between meso- and supergranular scales along the solar cycle.<p> <p><b>Conclusions.<b> The network magnetic field, produced locally at disk center independently from large scale dynamo, together with continuum contrast, vertical and horizontal flows, seem to remain constant during the solar cycle.<p>

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Physics
Authors :
Roudier, Th.
Malherbe, J. M.
Mirouh, G.
Date : 7 February 2017
DOI : 10.1051/0004-6361/201629274
Uncontrolled Keywords : Sun: atmosphere. Sun: photosphere. Sun: magnetic fields.
Depositing User : Clive Harris
Date Deposited : 08 Oct 2019 15:06
Last Modified : 08 Oct 2019 15:06

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