Relation between motion of matter in coronal holes and their evolution
We consider the evolution of a long-lived coronal hole (CH) from February to August 2002 in the range φ = -20° ÷ +15°, L = 30° ÷ 35°. Active formations occurred several times in it over its lifetime. After their extinction CH restored as it was before.
The Carrington rotation R1989 on May 12–26, 2002 has been studied in detail. For this rotation the relative CH areas on the basis of observations in the НеI 1083 nm line were determined. As a result of observations in the NiI 676.8 nm line (SOHO, MDI) the periods of the line-of-sight velocity variations have been detected. Variations of these periods in CH were compared with variations of CH areas. It appears that oscillation periods in photospheric layers of CH are connected linearly with CH areas in the chromosphere.
For the observation interval May 12–26, 2002 we distinguished 52 sites in coronal holes for which estimated area variations in the НеI 1083 nm line. For the moments similar to observations in the НеI 1083 nm line an average speed of vertical motion of matter on MDI data was detected. It was obtained that the growth of CH is accompanied by upward motion of matter at the photospheric level, and its decay – by downward motion.
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