1. Hyewon Jeong, Jongchul Chae Seoul National University
Evolutionary Characteristics of Magnetic Helicity Injection through Active Regions
Hyewon Jeong, Jongchul Chae
Seoul National University

2. Purpose How much helicity is supplied through active regions?
Does the helicity injection in an active region occurs intensively during a specific period or steadily through all of its lifetime?

3. Magnetic Helicity Magnetic helicity Relative magnetic helicity
Sum of linking numbers
over all pairs of closed field lines in a given volume
Relative magnetic helicity
Magnetic helicity relative to the helicity of potential field with the same magnetic flux at the photospheric boundary

4. Method (Chae’s method)
Helicity transfer equation
Apparent horizontal velocity of field line footpoint :
( LCT method)
Normal component of photospheric magnetic field :
(line-of-sight magnetogram data)
Vector potential for :
(Fourier Transform method)

5. Data and application line-of-sight magnetogram data (SoHO/MDI)
96min cadence
calculation for about 5 days away from the limb
6 active regions

6. AR 10696
1st rotation
2nd rotation

7. AR 10696

8. AR 10365
1st rotation
2nd rotation

9. AR 10365

10. Summary Active Regions (latitude, degree)
Helicity during the early phase
[Mx2/5day]
Final Total flux [Mx]
Differential rotation contribution [Mx2/5day]
AR (+8.16)
-21.0x1042
3.49x1022
-0.48x1042
AR (-7.34)
8.40x1042
3.61x1022
0.48x1042
AR (-20.39)
-13.5x1042
3.83x1022
1.3x1042
AR (-13.68)
-43.5x1042
6.20x1022
2.6x1042
AR (-9.93)
-2.45x1042
2.09x1022
0.22x1042
AR (-18.66)
-1.75x1042
1.41x1022
0.075x1042

11. Conclusion
Magnetic helicity is supplied intensively during the growth of active regions or during flux emergence.
The range of the amount of helicity injected :
The maximum helicity injection rate measured :
In conclusion we found that
Magnetic helicity is supplied intensively during the growth of active regions or during flux emergence.
The range of the amount of helicity injected is like this.
Lastly, the maximum helicity injection rate measured was like this.