SOLAR MAGNETIC HELICITY INJECTED INTO THE HELIOSPHERE: MAGNITUDE, BALANCE, AND PERIODICITIES OVER SOLAR CYCLE 23

作者：Georgoulis M K^*; Rust D M; Pevtsov A A; Bernasconi P N; Kuzanyan K M

来源：Astrophysical Journal Letters, 2009, 705(1): L48-L52.

DOI：10.1088/0004-637X/705/1/L48

• Sun: atmosphere
• Sun: coronal mass ejections (CMEs)
• Sun: magnetic fields
• Sun: photosphere

Relying purely on solar photospheric magnetic field measurements that cover most of solar cycle 23 (1996-2005), we calculate the total relative magnetic helicity injected into the solar atmosphere, and eventually shed into the heliosphere, over the latest cycle. Large active regions dominate the helicity injection process with similar to 5.7x10(45) Mx(2) of total injected helicity. The net helicity injected is less than or similar to 1% of the above output. Peculiar active-region plasma flows account for similar to 80% of this helicity; the remaining similar to 20% is due to solar differential rotation. The typical helicity per active-region CME ranges between (1.8-7) x 10(42) Mx(2) depending on the CME velocity. Accounting for various minor underestimation factors, we estimate a maximum helicity injection of similar to 6.6 x 10(45) Mx(2) for solar cycle 23. Although no significant net helicity exists over both solar hemispheres, we recover the well-known hemispheric helicity preference, which is significantly enhanced by the solar differential rotation. We also find that helicity injection in the solar atmosphere is an inherently disorganized, impulsive, and aperiodic process.

• 出版日期2009-11-1
• 单位中国科学院国家天文台