How to improve the maps of magnetic helicity injection in active regions?

AbstractThe helicity is important to present the basic topological configuration of magnetic field in solar atmosphere. The distribution of magnetic helicity in solar atmosphere is presented by means of the observational (vector) magnetograms. As the kinetic helicity in the solar subatmosphere can be inferred from the velocity field based on the technique of the helioseismology and used to compare with the magnetic helicity in the solar atmosphere, the observational helicities provide the important chance for the confirmation on the generation of magnetic fields in the subatmosphere and solar dynamo models also. In this paper, we present the observational magnetic and kinetic helicity in solar active regions and corresponding questions, except the relationship with solar eruptive phenomena.

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Studying the Transfer of Magnetic Helicity in Solar Active Regions with the Connectivity-based Helicity Flux Density Method

The Astrophysical Journal ◽

10.3847/1538-4357/aaa1e1 ◽

2018 ◽

Vol 852 (2) ◽

pp. 141 ◽

Cited By ~ 7

Author(s):

K. Dalmasse ◽

É. Pariat ◽

G. Valori ◽

J. Jing ◽

P. Démoulin

Keyword(s):

Flux Density ◽

Active Regions ◽

Magnetic Helicity ◽

Density Method ◽

Solar Active Regions

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Hemispheric injection of magnetic helicity by surface flux transport

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936475 ◽

2019 ◽

Vol 631 ◽

pp. A138 ◽

Cited By ~ 3

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.

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