Solar-Cycle, Radial and Latitudinal Variations of Magnetic Helicity: IMF Observations

2013 ◽  
pp. 239-245 ◽  
Author(s):  
Charles W. Smith
Keyword(s):  
Solar Cycle ◽  
Magnetic Helicity ◽  
Latitudinal Variations

scholarly journals Hemispheric injection of magnetic helicity by surface flux transport

2019 ◽  
Vol 631 ◽  
pp. A138 ◽  
Author(s):  
G. Hawkes ◽  
A. R. Yeates
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Rotation ◽  
Surface Flux ◽  
Magnetic Helicity ◽  
Solar Cycles ◽  
Flux Transport ◽  
Transport Models ◽  
Radial Magnetic Field ◽  
Helicity Injection

Aims. We estimate the injection of relative magnetic helicity into the solar atmosphere by surface flux transport over 27 solar cycles (1700–2009). Methods. We determine the radial magnetic field evolution using two separate surface flux transport models: one driven by magnetogram inputs and another by statistical active region insertion guided by the sunspot number record. The injection of relative magnetic helicity is then computed from this radial magnetic field together with the known electric field in the flux transport models. Results. Neglecting flux emergence, solar rotation is the dominant contributor to the helicity injection. At high latitudes, the injection is always negative/positive in the northern/southern hemisphere, while at low latitudes the injection tends to have the opposite sign when integrated over the full solar cycle. The overall helicity injection in a given solar cycle depends on the balance between these two contributions. This net injected helicity correlates well with the end-of-cycle axial dipole moment.

scholarly journals Large scale magnetic helicity fluxes estimated from MDI magnetic synoptic charts

2012 ◽  
Vol 8 (S294) ◽  
pp. 157-158
Author(s):  
Shangbin Yang ◽  
Hongqi Zhang
Keyword(s):  
Solar Cycle ◽  
Magnetic Flux ◽  
Solar Disk ◽  
Large Scale ◽  
Magnetic Helicity ◽  
Local Correlation ◽  
Solar Cycles ◽  
23Rd Solar Cycle ◽  
Term Evolution

AbstractTo investigate the characteristics of large scale and long term evolution of magnetic helicity with solar cycles, we use the method of Local Correlation Tracking (LCT) to estimate the magnetic helicity evolution over the 23rd solar cycle from 1996 to 2009 by using 795 MDI magnetic synoptic charts. The main results are: the hemispheric helicity rule still holds in general, i.e. the large-scale negative (positive) magnetic helicity dominates the northern (southern) hemisphere. However, the large scale magnetic helicity fluxes show the same sign in both hemispheres around 2001 and 2005. The global, large scale magnetic helicity flux over the solar disk changes from negative value at the beginning of the 23rd solar cycle to positive value at the end of the cycle, which also shows the similar trend from the normalized magnetic flux by using the magnetic flux. The net accumulated magnetic helicity is negative in the period between 1996 and 2009.

scholarly journals Evolution of Magnetic Helicity in Solar Cycle 24

2019 ◽  
Vol 877 (2) ◽  
pp. L36 ◽  
Author(s):  
Valery V. Pipin ◽  
Alexei A. Pevtsov ◽  
Yang Liu ◽  
Alexander G. Kosovichev
Keyword(s):  
Solar Cycle ◽  
Magnetic Helicity ◽  
Solar Cycle 24 ◽  
Cycle 24

scholarly journals Magnetic Helicity as a Predictor of the Solar Cycle

Solar Physics ◽  
2018 ◽  
Vol 293 (7) ◽  
Author(s):  
G. Hawkes ◽  
M. A. Berger
Keyword(s):  
Solar Cycle ◽  
Magnetic Helicity

scholarly journals Magnetic Helicity as a Predictor of the Solar Cycle

2017 ◽  
Vol 13 (S335) ◽  
pp. 20-22
Author(s):  
G. Hawkes ◽  
M. A. Berger
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Differential Rotation ◽  
Strong Predictor ◽  
Active Regions ◽  
Magnetic Helicity ◽  
Poloidal Field ◽  
Northern And Southern Hemispheres

AbstractIt is known that the poloidal field is at its maximum during solar minima, and that the behaviour during this time acts as a strong predictor of the strength of the following solar cycle. This relationship relies on the action of differential rotation (the Omega effect) on the poloidal field, which generates the toroidal flux observed in sunspots and active regions. We measure the helicity flux into both the northern and southern hemispheres using a model that takes account of the omega effect, which we find offers a strong quantification of the above relationship. We find that said helicity flux offers a strong prediction of solar activity up to 5 years in advance of the next solar cycle.

scholarly journals Magnetic Helicity Condensation and the Solar Cycle

2018 ◽  
Vol 869 (1) ◽  
pp. 62 ◽  
Author(s):  
Duncan H. Mackay ◽  
C. Richard DeVore ◽  
Spiro K. Antiochos ◽  
Anthony R. Yeates
Keyword(s):  
Solar Cycle ◽  
Magnetic Helicity
Sign in / Sign up

Export Citation Format

Share Document