Long-term cyclic variations of prominences, green and red coronae over solar cycles

2000 ◽  
Vol 21 (3-4) ◽  
pp. 201-204 ◽  
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Solar Cycles ◽  
Cyclic Variations

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

scholarly journals Grand minima of solar activity during the last millennia

2011 ◽  
Vol 7 (S286) ◽  
pp. 372-382 ◽  
Author(s):  
Ilya G. Usoskin ◽  
Sami K. Solanki ◽  
Gennady A. Kovaltsov
Keyword(s):  
Solar Activity ◽  
Historical Record ◽  
Moderate Activity ◽  
Solar Cycles ◽  
Cosmogenic Isotope ◽  
Cyclic Variations ◽  
Grand Maximum ◽  
Grand Minima ◽  
Stellar Dynamo

AbstractIn this review we discuss the occurrence and statistical properties of Grand minima based on the available data covering the last millennia. In particular, we consider the historical record of sunspot numbers covering the last 400 years as well as records of cosmogenic isotopes in natural terrestrial archives, used to reconstruct solar activity for up to the last 11.5 millennia, i.e. throughout the Holocene. Using a reconstruction of solar activity from cosmogenic isotope data, we analyze statistics of the occurrence of Grand minima. We find that: the Sun spends about most of the time at moderate activity, 1/6 in a Grand minimum and some time also in a Grand maximum state; Occurrence of Grand minima is not a result of long-term cyclic variations but is defined by stochastic/chaotic processes; There is a tendency for Grand minima to cluster with the recurrence rate of roughly 2000-3000 years, with a weak ≈210-yr periodicity existing within the clusters. Grand minima occur of two different types: shorter than 100 years (Maunder-type) and long ≈150 years (Spörer-type). It is also discussed that solar cycles (most possibly not sunspots cycle) could exist during the Grand minima, perhaps with stretched length and asymmetric sunspot latitudinal distribution.These results set new observational constraints on long-term solar and stellar dynamo models.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Computer-assisted long-term measurements of urinary output and other biological data

1990 ◽  
Vol 258 (1) ◽  
pp. R274-R280 ◽  
Author(s):  
H. W. Reinhardt ◽  
U. Palm ◽  
R. Mohnhaupt ◽  
K. Dannenberg ◽  
W. Boemke
Keyword(s):  
Sodium Excretion ◽  
Biological Data ◽  
Computer Assisted ◽  
Indwelling Catheters ◽  
Integrative Physiology ◽  
Short Intervals ◽  
Physiological Variables ◽  
Cyclic Variations ◽  
Computerized System

A computerized system is described, combining automatic collection of urine in short intervals (minutes) over long periods (days) and recordings of body temperature, MABP, and heart rate in chronically instrumented conscious dogs. During the studies the dogs are housed in metabolic cages. Indwelling catheters and electrical wires are connected to a specially designed swivel and directed out of the cage to the next room. Infusions, blood sampling, and monitoring can be performed from this room without disturbance to the dogs. Three examples of recordings are given. In one of these examples the sodium excretion patterns on 5 consecutive days under continuous saline infusion in one dog is evaluated. Urine was collected every 20 min. Sodium excretion showed cyclic variations. Fourier analysis exhibited 18-h periods and 4- to 8-h periods. The described system renders, e.g., coherent time series analysis possible for a variety of simultaneously recorded physiological variables and may thus acquire considerable importance for integrative physiology.

scholarly journals The Dimensional Stability and Durability of Acrylic Resins for the Injection of Cementitious Systems

2020 ◽  
Vol 4 (1) ◽  
pp. 75
Author(s):  
C. S. Paglia ◽  
A. Krattiger
Keyword(s):  
Dimensional Stability ◽  
Crack Formation ◽  
General Increase ◽  
Acrylic Resins ◽  
Material Stiffness ◽  
Cent Relative Humidity ◽  
Term Basis ◽  
Cyclic Variations ◽  
Cementitious Systems

The dimensional stability and durability of Acrylamide- and Methacrylate-based acrylic resins have been studied. The dimensional stability was characterized by measuring the volume expansion of samples immersed in water for a period up to 240 days or by exposing the samples to 23oC and 50 per cent, 90 per cent relative humidity and by monitoring the shrinkage. The durability was investigated by exposing the resins to cyclic variations of temperature in air and in water. The resins generally exhibit a significant volume change up to 160 per cent of the initial volume when immersed in water or exposed to a relatively dry atmosphere (23oC and 50 per cent). A general increase in the material stiffness and/or crack formation on the surface of the resin is observed. On a long-term basis, the durability of the resins may significantly vary with occasionally a partial or complete deterioration of the some resins. A general better dimensional stability and durability is observed for the Methacrylate-based resins as compared to the Acrylamide-based resins.

scholarly journals Large-Scale Patterns of Prominences in the Global Solar Cycles During 1880–1995

1998 ◽  
Vol 167 ◽  
pp. 442-445
Author(s):  
Dirk K. Callebaut ◽  
Valentine I. Makarov ◽  
Ksenia S. Tavastsherna
Keyword(s):  
Large Scale ◽  
Wolf Number ◽  
Solar Cycles ◽  
Zonal Distribution ◽  
Periodic Oscillations ◽  
Period 1880 ◽  
Latitude Distribution ◽  
The Mean ◽  
Long Term Variations

AbstractThe zonal distribution of prominences, their poleward migration from the sunspot zone to the poles, the polar magnetic field reversals and a correlation of the mean latitude of filament bands at minimum activity with the maximum of Wolf number in the next cycle are briefly discussed for the period 1880–1995. The need for research on the longterm latitude distribution of the prominences is emphasized. New results concerning long-term variations of the torsional oscillations of the Sun and quasi-periodic oscillations of the latitude zonal boundaries from an analysis of Hα charts (1915–1990) are given.

scholarly journals The Long-Term Behaviour of BY Dra

1995 ◽  
Vol 151 ◽  
pp. 103-105
Author(s):  
K.P. Panov ◽  
M.S. Ivanovo ◽  
J.S.W. Stegert
Keyword(s):  
Activity Cycle ◽  
Light Level ◽  
Light Curves ◽  
Sunspot Activity ◽  
The Past ◽  
Cyclic Variations ◽  
The Mean ◽  
Subsequent Rise ◽  
Visual Light

BY Dra has been extensively monitored for flares and spot-modulation of brightness at the Bulgarian National Astronomical Observatory (Panov & Ivanova 1993). Its mean light level exhibited remarkable changes in the past, due to the emergence and disintegration of photospheric spots, and different cycles have been proposed for the long-term changes of the BY Dra activity. This star is still believed to be a good candidate for cyclic variations, presumably similar to the sunspot activity cycle. After a spectacular drop in brightness in 1965 — 1967, and a subsequent rise in the early 70s, the mean light remained approximately constant during 1977 - 1991. A brightening of BY Dra occurred in 1992.In Fig. 1, the light curves are shown for 1991, 1992 and 1993 in the V-band and in B — V. Phases were calculated with the ephemeris of Chugainov (1966):JD (min. light) = 2438983.612 + 3.836 · EFrom Fig. 1, it is apparent that the mean visual light, which was about V = 8.20 in 1991, increased in 1992 by 0m.10, and a further increase by another 0m.03 occurred in 1993. The phase of minimum light in 1992 indicates that the position of the spot remained approximately the same in stellar longitude as in 1991. However, in 1993 the position of the spot changed by almost half a period.

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 The long-term effects of space weather on satellite operations

2010 ◽  
Vol 28 (6) ◽  
pp. 1361-1367 ◽  
Author(s):  
D. T. Welling
Keyword(s):  
Background Radiation ◽  
High Energy ◽  
High Energy Particle ◽  
Solar Cycles ◽  
Long Term Effects ◽  
Radiation Background ◽  
Particle Exposure ◽  
Total Lifetime ◽  
The Impact

Abstract. Integrated lifetime radiation damage may cause spacecraft to become more susceptible to operational anomalies by changing material characteristics of electronic components. This study demonstrates and quantifies the impact of these effects by examining the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center (NGDC) satellite anomaly database. Energetic particle data from the Geostationary Operational Environmental Satellites (GOES) is used to construct the total lifetime particle exposure a satellite has received at the epoch of an anomaly. These values are compared to the satellite's chronological age and the average exposure per year (calculated over two solar cycles.) The results show that many anomalies occur on satellites that have received a total lifetime high-energy particle exposure that is disproportionate to their age. In particular, 10.8% of all events occurred on satellites that received over two times more 20 to 40 MeV proton lifetime particle exposure than predicted using an average annual mean. This number inflates to 35.2% for 40 to 80 MeV protons and 33.7% for ≥2 MeV electrons. Overall, 73.5% of all anomalies occurred on a spacecraft that had experienced greater than two times the expected particle exposure for one of the eight particle populations used in this study. Simplistically, this means that the long term radiation background exposure matters, and that if the background radiation is elevated during the satellite's lifetime, the satellite is likely to experience more anomalies than satellites that have not been exposed to the elevated environment.

Long-term solar cycles according to data on the cosmogenic beryllium concentration in ice of central Greenland

2010 ◽  
Vol 50 (4) ◽  
pp. 475-481 ◽  
Author(s):  
M. G. Ogurtsov
Keyword(s):  
Solar Cycles
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