Naslov
An estimate of microwave low brightness temperature regions' heights obtained measuring their rotation velocity

Autori
Brajša, Roman ; Ruždjak, Vladimir ; Vršnak, Bojan ; Woehl, Hubertus ; Pohjolainen, Silja ; Urpo, Seppo

Izvornik
Solar Physics (0038-0938) 184 (1999), 2; 281-296

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Sažetak
Daily full-disk solar maps obtained at 37 GHz in the years 1979, 1980, 1981, 1982, 1987, 1988, 1989, 1990, and 1991 are analysed and compared with full-disk solar maps in H-alpha. A search for a difference in the measured angular rotation velocity for two classes of microwave low-brightness-temperature regions (LTRs), associated and not associated wiht H-alpha filaments, is performed. Procedures with and without statistical weights, assigned to angular rotation velocities acording to the tracing time, are applied ant the statistical significance of the results are discussed. A higher angular rotation velocity is measured for LTRs associated with H-alpha filaments than for the not-associated ones. This angular velocity difference is interpreted as a consequence of a height difference between these two types of LTR tracers. Changes of the solar differential rotation velocity during the activity cycle measured using LTRs as tracers are explained by the measured cycle-dependance of the association rate between LTRs and H-alpha filaments. Similarly, the north - south asymmetry in the solar rotation velocity measured tracing LTRs is explained by the measured north - south asymmetry in the association rate between LTRs and H-alpha filaments. The rotation velocity of LTRs and H-alpha filaments is on the average more rigid in comparison with sunspots.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA