Are granules good tracers of solar surface velocity fields?

被引:60
作者
Rieutord, M
Roudier, T
Ludwig, HG
Nordlund, Å
Stein, R
机构
[1] Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France
[2] Inst Univ France, Paris, France
[3] Observ Midi Pyrenees, Astrophys Lab, F-65008 Tarbes, France
[4] Lund Observ, S-22100 Lund, Sweden
[5] Ecole Normale Super Lyon, CRAL, F-69364 Lyon, France
[6] NBIfAFG, Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark
[7] NBIfAFG, Astron Observ, DK-2100 Copenhagen, Denmark
[8] Michigan State Univ, E Lansing, MI 48824 USA
关键词
convection; Sun : granulation; Sun : photosphere;
D O I
10.1051/0004-6361:20011160
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Using a numerical simulation of compressible convection with radiative transfer mimicking the solar photosphere, we compare the velocity field derived from granule motions to the actual velocity field of the plasma. We thus test the idea that granules may be used to trace large-scale velocity fields at the sun's surface. Our results show that this is indeed the case provided the scale separation is sufficient. We thus estimate that neither velocity fields at scales less than 2500 km nor time evolution at scales shorter than 0.5 hr can be faithfully described by granules. At larger scales the granular motions correlate linearly with the underlying fluid motions with a slope of less than or similar to2 reaching correlation coefficients up to similar to 0.9.
引用
收藏
页码:L14 / L17
页数:4
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