Intermittency spectra of current helicity in solar active regions

Kutsenko, A. S.; Abramenko, V. I.; Kuzanyan, K. M.; Xu, Haiqing; Zhang, Hongqi

doi:10.1093/mnras/sty2109

Cited by 8 publications

(6 citation statements)

References 38 publications

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“…The magnetic power spectrum also has a power-law form [34], [35]. The power-law form is also inherent in the spatial characteristics of the current helicity in active regions [36]. We found that for the 48 active regions considered, the absolute value of the power function exponent of |j z |-distribution is concentrated in the vicinity of 3.69 with a small standard deviation of 0.51.…”

Section: Discussionmentioning

confidence: 71%

Density distribution of photospheric vertical electric currents in flare active regions of the Sun

Zimovets¹,

Nechaeva²,

Sharykin³

et al. 2019

Preprint

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Solar active regions contain electric currents. Information on the distribution of currents is important for understanding the processes of energy release on the surface of the Sun and in the overlying layers. The paper presents an analysis of the probability density function (PDF) of the absolute value of the photospheric vertical electric current density (|j z |) in 48 active regions before and after flares in 2010-2017. Calculation of |j z | is performed by applying the differential form of Ampere's circuital law to photospheric vector magnetograms obtained from observations of the Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO). It has been established that for the studied active regions PDF(|j z |) is described by the Gauss function in the low-|j z | region (|j z | < 10110 ± 1321 statampere/cm 2 ) and the decaying power-law function in the region of higher |j z | values. Also, for some active regions PDF(|j z |) can be described by the special kappa-function. The distributions of the parameters of the approximating functions are obtained using the least squares method. The average absolute value of the power-law function index is 3.69 ± 0.51, and 3.99 ± 0.51 of the kappa-function. No systematic changes in parameters during the flares are detected. An explicit connection between the parameters and the flare X-ray class, as well as with the Hale magnetic class of the active regions, is not found. Arguments are presented in favor of the suggestion that the Gaussian distribution in the low-value region of PDF(|j z |) represents noise in the data, while the power-law "tail" reflects the nature of electric currents in the solar active regions.

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Section: Discussionmentioning

confidence: 71%

Density distribution of photospheric vertical electric currents in flare active regions of the Sun

Zimovets¹,

Nechaeva²,

Sharykin³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Probably, new methods for early detection of emerging magnetic flux, for example, by means of helioseismology (e.g., Birch et al 2019;Dhuri et al 2020), could increase the forecast interval. The distortion of the electric current system of a pre-existing AR by an emerging satellite, which was discussed in Kutsenko et al (2018), could also be used in the forecast.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

A Statistical Study of Magnetic Flux Emergence in Solar Active Regions Prior to Strongest Flares

Kutsenko,

Abramenko,

Plotnikov

2024

Res. Astron. Astrophys.

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Using the data on magnetic field maps and continuum intensity for Solar Cycles 23 and 24, we explored 100 active regions (ARs) that produced M5.0 or stronger flares. We focus on the presence/absence of the emergence of magnetic flux in these ARs 2-3 days before the strong flare onset. We found that 29 ARs in the sample emerged monotonously amidst quiet-Sun. A major emergence of a new magnetic flux within pre-existing AR yielding the formation of a complex flare-productive configuration was observed in another 24 cases. For 30 ARs, an insignificant (in terms of the total magnetic flux of pre-existing AR) emergence of a new magnetic flux within the pre-existing magnetic configuration was observed; for some of them the emergence resulted in a formation of a configuration with a small $\delta$-sunspot. 11 out of 100 ARs exhibited no signatures of magnetic flux emergence during the entire interval of observation. In 6 cases the emergence was in progress when the AR appeared on the Eastern limb, so that the classification and timing of emergence were not possible. We conclude that the recent flux emergence is not a necessary and/or sufficient condition for strong flaring of an AR. The flux emergence rate of analyzed here flare-productive ARs was compared with that of flare-quiet ARs analyzed in our previous studies. We revealed that the flare-productive ARs tend to display faster emergence than the flare-quiet ones do.

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“…Birch et al 2019;Dhuri et al 2020), could increase the forecast interval. The distortion of the electric current system of a pre-existing AR by an emerging satellite, which was discussed in Kutsenko et al (2018), could also be used in the forecast.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

A statistical study of magnetic flux emergence in solar active regions prior to strongest flares

Kutsenko¹,

Abramenko²,

Plotnikov³

2021

Preprint

View full text Add to dashboard Cite

Using the data on magnetic field maps and continuum intensity for Solar Cycles 23 and 24, we explored 100 active regions (ARs) that produced M5.0 or stronger flares. We focus on the presence/absence of the emergence of magnetic flux in these ARs 2-3 days before the strong flare onset. We found that 29 ARs in the sample emerged monotonously amidst quiet-Sun area. A major emergence of a new magnetic flux within pre-existing AR yielding the formation of a complex flare-productive configuration was observed in another 24 cases. For 30 ARs, an insignificant (in terms of the total magnetic flux of pre-existing AR) emergence of a new magnetic flux within the pre-existing magnetic configuration was observed; for some of them the emergence resulted in a formation of a configuration with a small -sunspot. 11 out of 100 ARs exhibited no signatures of magnetic flux emergence during the entire interval of observation. In 6 cases the emergence was in progress when the AR appeared on the Eastern limb, so that the classification and timing of emergence were not possible. We conclude that the recent flux emergence is not a necessary and/or sufficient condition for strong flaring of an AR. The flux emergence rate of analysed here flare-productive ARs was compared with that for flare-quiet ARs analysed in our previous studies. We revealed that the flare-productive ARs tend to display faster emergence than the flare-quiet ones.

show abstract

Intermittency spectra of current helicity in solar active regions

Cited by 8 publications

References 38 publications

Density distribution of photospheric vertical electric currents in flare active regions of the Sun

Density distribution of photospheric vertical electric currents in flare active regions of the Sun

A Statistical Study of Magnetic Flux Emergence in Solar Active Regions Prior to Strongest Flares

A statistical study of magnetic flux emergence in solar active regions prior to strongest flares

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