scholarly journals Statistical studies of duration of low-power solar flares

2018 ◽  
pp. 8-16 ◽  
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Flare Region ◽  
Statistical Studies ◽  
Time Parameters ◽  
The Mean ◽  
Using Data

This paper is a sequel to papers dealing with time parameters of solar flares in the Hα line. Using data from the international flare patrol for 1972–2010, we have determined the mean duration of flares of different importance and classes of area. We have established that 94.6 % of flares last more than 60 min. The duration of 90 % of flares with min is 2.1–3.3 hrs. In rare cases, flares can last about 12 hrs. The duration of powerful solar flares does not exceed 8.3 hrs. We have found that the duration of solar flares depends on features of their development. Flares with one brilliant point in the flare region have the shortest duration; two-ribbon flares and flares exhibiting several intensity maxima have the longest duration. We have confirmed that the duration of flares increases with increasing classes of area and brightness.

scholarly journals Statistical studies of duration of low-power solar flares

2018 ◽  
Vol 4 (2) ◽  
pp. 8-16
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Flare Region ◽  
Statistical Studies ◽  
Time Parameters ◽  
The Mean ◽  
Using Data

This paper is a sequel to papers dealing with time parameters of solar flares in the Hα line. Using data from the international flare patrol for 1972–2010, we have determined the mean duration of flares of different importance and classes of area. We have established that 94.6 % of flares last more than 60 min. The duration of 90 % of flares with min is 2.1–3.3 hrs. In rare cases, flares can last about 12 hrs. The duration of powerful solar flares does not exceed 8.3 hrs. We have found that the duration of solar flares depends on features of their development. Flares with one brilliant point in the flare region have the shortest duration; two-ribbon flares and flares exhibiting several intensity maxima have the longest duration. We have confirmed that the duration of flares increases with increasing classes of area and brightness.

scholarly journals Statistical studies of duration of low-power solar flares

2018 ◽  
Vol 4 (2) ◽  
pp. 35-46
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Flare Region ◽  
Statistical Studies ◽  
Time Parameters ◽  
Using Data

This paper is a sequel to papers dealing with time parameters of solar flares in the Hα line. Using data from the international flare patrol for 1972–2010, we have determined mean duration of flares of different importance and classes of area. We have established that 94.6 % of flares last more than 60 min. The duration of 90 % of flares with min is 2.1–3.3 hrs. In rare cases, flares can last about 12 hrs. The duration of powerful solar flares does not exceed 8.3 hrs. We have found that the duration of solar flares de-pends on features of their development. Flares with one brilliant point in the flare region have the shortest duration; two-ribbon flares and flares exhibiting several intensity maxima have the longest duration. We have confirmed that the duration of flares increases with increasing classes of area and brightness.

scholarly journals Statistical research into low-power solar flares. Main phase duration

2017 ◽  
pp. 5-16 ◽  
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Statistical Analysis ◽  
Low Power ◽  
Solar Flares ◽  
Main Phase ◽  
Electronic Database ◽  
Statistical Research ◽  
Phase Duration ◽  
Long Duration ◽  
Time Parameters ◽  
Using Data

This paper is a sequel to earlier papers on time parameters of solar flares in the Hα line. Using data from the International Flare Patrol, an electronic database of solar flares for the period 1972–2010 has been created. The statistical analysis of the duration of the main phase has shown that it increases with increas-ing flare class and brightness. It has been found that the duration of the main phase depends on the type and features of development of solar flares. Flares with one brilliant point have the shortest main phase; flares with several intensity maxima and two-ribbon flares, the longest one. We have identified more than 3000 cases with an ultra-long duration of the main phase (more than 60 minutes). For 90 % of such flares the duration of the main phase is 2–3 hrs, but sometimes it reaches 12 hrs.

scholarly journals Statistical research into low-power solar flares. Main phase duration

2017 ◽  
Vol 3 (4) ◽  
pp. 5-16 ◽  
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Statistical Analysis ◽  
Low Power ◽  
Solar Flares ◽  
Main Phase ◽  
Electronic Database ◽  
Statistical Research ◽  
Phase Duration ◽  
Long Duration ◽  
Time Parameters ◽  
Using Data

This paper is a sequel to earlier papers on time parameters of solar flares in the Hα line. Using data from the International Flare Patrol, an electronic database of solar flares for the period 1972–2010 has been created. The statistical analysis of the duration of the main phase has shown that it increases with increasing flare class and brightness. It has been found that the duration of the main phase depends on the type and features of development of solar flares. Flares with one brilliant point have the shortest main phase; flares with several intensity maxima and two-ribbon flares, the longest one. We have identified more than 3000 cases with an ultra-long duration of the main phase (more than 60 minutes). For 90 % of such flares the duration of the main phase is 2–3 hrs, but sometimes it reaches 12 hrs.

scholarly journals Distribution of low-power solar flares by brightness rise time

2018 ◽  
Vol 4 (3) ◽  
pp. 5-16
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Rise Time ◽  
Electronic Database ◽  
Filament Activation ◽  
Explosive Phase ◽  
The Mean ◽  
Using Data ◽  
Brightness Decay ◽  
Developmental Features

Using data from the international flare patrol for 1972–2010, we have formed an electronic database for more than 123 thousand solar flares. We determined the mean brightness rise time (flash-phase) for flare area classes and importance. We show that the mean flash phase increased with increasing area class. For brightness classes this trend is less pronounced. We have found that flares with explosive phase and flares with one brilliant point have the shortest flash phases; two-ribbon flares and flares with several intensity maxima, the longest ones. We have separated 572 cases when the brightness rise time was more than 60 min; 80 % of such ultra-long flares have a shorter brightness decay time (main phase). We have established that low-power flares in terms of developmental features do not differ from large flares. Low-power solar flares, as well as large flares, can be followed by filament activation or disappearance, and can have an explosive phase and several intensity maxima. Two-ribbon flares, white-light flares, and flares covering sunspot umbra can also have low power.

scholarly journals Statistical studies of low-power solar flares. Distribution of flares by area, brightness, and classes

2017 ◽  
Vol 3 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Software Package ◽  
Statistical Data ◽  
Correlation Coefficients ◽  
Flare Activity ◽  
The Sun ◽  
Electronic Database ◽  
First Results ◽  
Statistical Studies

An electronic database has been created for 123801 solar flares that occurred on the Sun over the period from 1972 to 2010. It is based on catalogs of the Solar Geophysical Data (SGD) and Quarterly Bulletin on Solar Activity. A software package has been used for statistical data preprocessing. The first results revealed a number of new features in the distribution of parameters of solar flares, which differ from those obtained previously. We have found that more than 90 % of all solar flares are low-power. The most numerous class comprises SF flares (64 %). Flare activity shows a pronounced cyclicity and high correlation with Wolf numbers. The highest correlation coefficients indicate S and 1 solar flares. There is also a high correlation between individual flare classes: S and 1, 1 and (2–4). The results obtained previously [Mitra et al., 1972] which provide evidence of the prevalence of SN solar flares (47 %) and the existence of significant peaks for SN and 1N flares, have not been confirmed. The distri-bution of the number of solar flares with increasing op-tical importance smoothly decreases without significant deviations. With increasing optical importance, solar flares are gradually redistributed toward an increase in brightness class. The excess of the number of SN and 1N solar flares present in the distributions obtained in [Mitra et al., 1972] are most likely associated with poor statistics.

scholarly journals Statistical studies of low-power solar flares. Distribution of flares by area, brightness, and classes

2017 ◽  
Vol 3 (1) ◽  
pp. 40-56 ◽  
Author(s):  
Александр Боровик ◽  
Aleksandr Borovik ◽  
Антон Жданов ◽  
Anton Zhdanov
Keyword(s):  
Low Power ◽  
Solar Flares ◽  
Software Package ◽  
Statistical Data ◽  
Correlation Coefficients ◽  
Flare Activity ◽  
The Sun ◽  
Electronic Database ◽  
First Results ◽  
Statistical Studies

An electronic database has been created for 123801 solar flares that occurred on the Sun over the period from 1972 to 2010. It is based on catalogs of the Solar Geophysical Data (SGD) and Quarterly Bulletin on Solar Activity. A software package has been used for statistical data preprocessing. The first results revealed a number of new features in the distribution of parameters of solar flares, which differ from those obtained previously. We have found that more than 90% of all solar flares are low-power. The most numerous class comprises SF flares (64%). Flare activity shows a pronounced cyclicity and high correlation with Wolf numbers. The highest correlation coefficients indicate S and 1 solar flares. There is also a high correlation between individual flare classes: S and 1, 1 and (2–4). The results obtained previously [Mitra et al., 1972] which provide evidence of the prevalence of SN solar flares (47%) and the existence of significant peaks for SN and 1N flares, have not been confirmed. The distribution of the number of solar flares with increasing optical importance smoothly decreases without significant deviations. With increasing optical importance, solar flares are gradually redistributed toward an increase in brightness class. The excess of the number of SN and 1N solar flares present in the distributions obtained in [Mitra et al., 1972] are most likely associated with poor statistics.

scholarly journals LOW-POWER SOLAR FLARES OF OPTICAL AND X-RAY WAVELENGTHS FOR SOLAR CYCLES 21–24

2020 ◽  
Vol 6 (3) ◽  
pp. 18-25
Author(s):  
Aleksandr Borovik ◽  
Anton Zhdanov
Keyword(s):  
Solar Activity ◽  
Low Power ◽  
Solar Flares ◽  
Optical Emission ◽  
Flare Activity ◽  
X Rays ◽  
Solar Cycles ◽  
X Ray ◽  
Cycle 24 ◽  
Using Data

Using data obtained in optical and X-ray wavelengths, we have analyzed solar flare activity for cycles 21–24. Over the last three cycles, solar activity is shown to decrease significantly. As compared to solar cycle 21 (the most active over the last 50 years), in cycle 24 2–4-class large optical flares are 4.4 times rarer; 1-class flares, 8.2 times; and S-class small flares, 4.1 times. The number of X-class flares decreased 3.7 times; M-class flares, 3.2 times. This confirms that secular solar activity trends affect peak values of 11-year cycles. It is shown that optical low-power flares can be accompanied by proton fluxes and X-ray bursts of different intensity, including X-class ones. Ranges of small flare emission in soft X-rays largely overlap with emission ranges of flares of high optical classes. We have confirmed that X-ray emission from solar flares appears on average 2 min before the optical emission. The X-ray maximum for small optical flares and 1-class flares occurs approximately 1 min later; for 2–4-class flares, 2 min.

scholarly journals LOW-POWER SOLAR FLARES OF OPTICAL AND X-RAY WAVELENGTHS FOR SOLAR CYCLES 21–24

2020 ◽  
Vol 6 (3) ◽  
pp. 16-22
Author(s):  
Aleksandr Borovik ◽  
Anton Zhdanov
Keyword(s):  
Solar Activity ◽  
Low Power ◽  
Solar Flares ◽  
Optical Emission ◽  
Flare Activity ◽  
X Rays ◽  
Solar Cycles ◽  
X Ray ◽  
Cycle 24 ◽  
Using Data

Using data obtained in optical and X-ray wavelengths, we have analyzed solar flare activity for cycles 21–24. Over the last three cycles, solar activity is shown to decrease significantly. As compared to solar cycle 21 (the most active over the last 50 years), in cycle 24 2–4-class large optical flares are 4.4 times rarer; 1-class flares, 8.2 times; and S-class small flares, 4.1 times. The number of X-class flares decreased 3.7 times; M-class flares, 3.2 times. This confirms that secular solar activity trends affect peak values of 11-year cycles. It is shown that optical low-power flares can be accompanied by proton fluxes and X-ray bursts of different intensity, including X-class ones. Ranges of small flare emission in soft X-rays largely overlap with emission ranges of flares of high optical classes. We have confirmed that X-ray emission from solar flares appears on average 2 min before the optical emission. The X-ray maximum for small optical flares and 1-class flares occurs approximately 1 min later; for 2–4-class flares, 2 min.

Comparison of phaco time parameters in eyes with and without glaucoma filtration surgery due to pseudoexfoliation glaucoma

2021 ◽  
pp. 112067212110177
Author(s):  
Ayse Gul Kocak Altintas ◽  
Cagri Ilhan
Keyword(s):  
Clinical Characteristics ◽  
Pseudoexfoliation Glaucoma ◽  
Filtration Surgery ◽  
Glaucoma Filtration Surgery ◽  
Mean Values ◽  
Time Parameters ◽  
The Mean ◽  
Group 2 ◽  
Surgical Manipulations ◽  
Phaco Time

Purpose: To compare the phaco time parameters including ultrasound time (UST), effective phaco time (EPT), and average phaco power (APP) in eyes with pseudoexfoliation glaucoma (PEG) and had or had not glaucoma filtration surgery. Methods: In this retrospective comparative study, Group 1 was constructed with 84 PEG patients who had not operated previously, and Group 2 was constructed with 49 PEG patients who had glaucoma filtration surgery. The mean values of UST, EPT, and APP were compared. The preoperative clinical characteristics and surgical manipulations were also compared. Results: The mean ages and male-to-female ratios of the groups were similar ( p > 0.05, for both). There was no difference in the preoperative clinical characteristics, including biometric values between the groups ( p > 0.05, for all). Some surgical manipulations, including pupillary stretching ( p = 0.004), pupillary membrane peeling ( p = 0.021), iris hook using ( p = 0.041), and capsular tension ring implantation ( p = 0.041), were significantly performed more commonly in Group 2. Although the mean UST and EPT values were similar ( p > 0.05, for both), the mean APP value was significantly lower in Group 2 ( p = 0.011). Conclusion: The lower APP parameter was observed in PEG patients having had glaucoma filtration surgery. Needing more surgical manipulation to overcome poor pupillary dilation and weak zonular instability can be a reason for this result.

Sign in / Sign up

Export Citation Format

Share Document