scholarly journals Disparity among low first ionization potential elements

2018 ◽  
Vol 619 ◽  
pp. A79 ◽  
Author(s):  
Verena Heidrich-Meisner ◽  
Lars Berger ◽  
Robert F. Wimmer-Schweingruber
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Ionization Potential ◽  
Charge State ◽  
Qualitative Difference ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Slow Solar Wind ◽  
Activity Maximum ◽  
First Ionization Potential

Context. The elemental composition of the solar wind differs from the solar photospheric composition. Elements with low first ionization potential (FIP) appear enhanced compared to O in the solar wind relative to the respective photospheric abundances. This so-called FIP effect is different in the slow solar wind and the coronal hole wind. However, under the same plasma conditions, for elements with similar FIPs such as Mg, Si, and Fe, comparable enhancements are expected. Aims. We scrutinize the assumption that the FIP effect is always similar for different low FIP elements, namely Mg, Si, and Fe. Methods. Here we investigate the dependency of the FIP effect of low FIP elements on the O7+/O6+ charge state ratio depending on time, that is the solar activity cycle, and solar wind type. In addition, we order the observed FIP ratios with respect to the O7+/O6+ charge state ratio into bins and analyze separately the respective distributions of the FIP ratio of Mg, Si, and Fe for each O7+/O6+ charge state ratio bin. Results. We observe that the FIP effect shows the same qualitative yearly behavior for Mg and Si, while Fe shows significant differences during the solar activity maximum and its declining phase. In each year, the FIP effect for Mg and Si always increases with increasing O7+/O6+ charge state ratio, but for high O7+/O6+ charge state ratios the FIP effect for Fe shows a qualitatively different behavior. During the years 2001–2006, instead of increasing with the O7+/O6+ charge state ratio, the Fe FIP ratio exhibits a broad peak or plateau. In addition, the FIP distribution per O7+/O6+ charge state bin is significantly broader for Fe than for Mg and Si. Conclusions. These observations support the conclusion that the elemental fractionation is only partly determined by FIP. In particular, the qualitative difference in behavior with increasing O7+/O6+ charge state ratio between Fe on the one hand and Mg and Si on the other hand is not yet well explained by models of fractionation.

scholarly journals Proton-proton collisional age to order solar wind types

2020 ◽  
Vol 636 ◽  
pp. A103
Author(s):  
Verena Heidrich-Meisner ◽  
Lars Berger ◽  
Robert F. Wimmer-Schweingruber
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Activity ◽  
Classification Scheme ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Slow Solar Wind ◽  
Threshold Values ◽  
Proton Proton ◽  
Solar Wind Parameters

Context. The properties of a solar wind stream are determined by its source region and by transport effects. Independently of the solar wind type, the solar wind measured in situ is always affected by both. This means that reliably determining the solar wind type from in situ observations is useful for the analysis of its solar origin and its evolution during the travel time to the spacecraft that observes the solar wind. In addition, the solar wind type also influences the interaction of the solar wind with other plasma such as Earth’s magnetosphere. Aims. We consider the proton-proton collisional age as an ordering parameter for the solar wind at 1 AU and explore its relation to the solar wind classification scheme developed by Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70). We use this to show that explicit magnetic field information is not required for this solar wind classification. Furthermore, we illustrate that solar wind classification schemes that rely on threshold values of solar wind parameters should depend on the phase in the solar activity cycle since the respective parameters change with the solar activity cycle. Methods. The categorization of the solar wind following Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70) was taken as our reference for determining the solar wind type. Based on the observation that the three basic solar wind types from this categorization cover different regimes in terms of proton-proton collisional age acol, p-p, we propose a simplified solar wind classification scheme that is only based on the proton-proton collisional age. We call the resulting method the PAC solar wind classifier. For this purpose, we derive time-dependent threshold values in the proton-proton collisional age for two variants of the proposed PAC scheme: (1) similarity-PAC is based on the similarity to the full Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70) scheme, and (2) distribution-PAC is based directly on the distribution of the proton-proton collisional age. Results. The proposed simplified solar wind categorization scheme based on the proton-proton collisional age represents an equivalent alternative to the full Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70) solar wind classification scheme and leads to a classification that is very similar to the full Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70) scheme. The proposed PAC solar wind categorization separates coronal hole wind from helmet-streamer plasma as well as helmet-streamer plasma (slow solar wind without a current sheet crossing) from sector-reversal plasma (slow solar wind with a current sheet crossing). Unlike the full Xu & Borovsky (2015, J. Geophys. Res.: Space Phys., 120, 70) scheme, PAC does not require information on the magnetic field as input. Conclusions. The solar wind is well ordered by the proton-proton collisional age. This implies underlying intrinsic relationships between the plasma properties, in particular, proton temperature and magnetic field strength in each plasma regime. We argue that sector-reversal plasma is a combination of particularly slow and dense solar wind and most stream interaction boundaries. Most solar wind parameters (e.g., the magnetic field strength, B, and the oxygen charge state ratio no7+/no6+) change with the solar activity cycle. Thus, all solar wind categorization schemes based on threshold values need to be adapted to the solar activity cycle as well. Because it does not require magnetic field information but only proton plasma measurements, the proposed PAC solar wind classifier can be applied directly to solar wind data from the Solar and Heliospheric Observatoty (SOHO), which is not equipped with a magnetometer.

scholarly journals The Observed Relationships Between Some Solar Rotation Parameters and the Activity Cycle

1983 ◽  
Vol 102 ◽  
pp. 99-111
Author(s):  
Robert Howard ◽  
Barry J. LaBonte
Keyword(s):  
Solar Activity ◽  
Solar Rotation ◽  
Rotational Velocity ◽  
Torsional Oscillation ◽  
Periodic Oscillation ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Activity Minimum ◽  
Activity Maximum ◽  
Open Question

Several parameters of the solar rotation show variations which appear to relate to the phase of the solar activity cycle. The latitude gradient of the differential rotation, as seen in the coefficients of the sin2 and sin4 terms in the latitude expansion, shows marked variations with the cycle. One of these variations may be described as a one-cycle-per-hemisphere torsional oscillation with a period of 11 years, where the high latitudes rotate faster at solar activity maximum and slower at minimum, and the low latitudes rotate faster at solar activity minimum and slower at maximum. Another variation is a periodic oscillation of the fractional difference in the low-latitude rotation between north and south hemispheres. The possibility of a variation in the absolute rotational velocity of the sun in phase with the solar cycle remains an open question. The two-cycle-per-hemisphere torsional waves in the solar rotation also represent an aspect of the rotation which varies with the cycle. We show that the amplitude of the fast flowing zone rises a year before the rise to activity maximum. The fast zone seems to be physically the more significant of the two zones.

scholarly journals Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

2018 ◽  
pp. 33-58
Author(s):  
Геннадий Минасянц ◽  
Gennady Minasyants ◽  
Тамара Минасянц ◽  
Tamara Minasyants ◽  
Владимир Томозов ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Cosmic Rays ◽  
Ionization Potential ◽  
Solar Minimum ◽  
Geomagnetic Storms ◽  
Galactic Cosmic Rays ◽  
Ion Fluxes ◽  
Ion Energy ◽  
First Ionization Potential

We report the results of the investigation into plasma physical characteristics at various solar activity manifestations and in periods of their absence. These results have been obtained from quantitative estimates of the relative abundance of Fe/O ions in different energy ranges. Maximum values of the Fe/O ratio is shown to correspond to particle fluxes from impulsive flares for ions with energies <2 MeV/n (the most significant manifestation of the FIP effect). In particle fluxes from gradual flares, the Fe/O value decreases smoothly with ion energy and is noticeably inferior to values of fluxes in impulsive events. We have established that the properties of flares of solar cosmic rays indicate their belonging to a separate subclass in the total population of gradual events. Relying on variations in the abundance of Fe/O ions, we propose an xplanation of the solar plasma behavior during the development of flares of both classes. Magnetic clouds (a separate type of coronal mass ejections (CME)), which have regions of turbulent compression and are sources of strong geomagnetic storms, exhibit a relative composition of Fe ions comparable to the abundance of Fe in ion fluxes from gradual flares. We have found out that the Fe/O value can be used to detect penetration of energetic flare plasma into the CME body at the initial phase of their joint development and to estimate its relative contribution. During solar minimum with complete absence of sunspots, the Fe/O ratio during periods of “quiet” solar wind show absolutely low values of Fe/O=0.004–0.010 in the energy range from 2–5 to 30 MeV/n. This is associated with the manifestation of the cosmic ray anomalous component, which causes an increase in the intensity of ion fluxes with a high first ionization potential, including oxygen (O), and elements with a low first ionization potential (Fe) demonstrate weakening of the fluxes. As for particles with higher energies (Ek>30 MeV/n), the Fe/O increase is due to the decisive influence of galactic cosmic rays on the composition of impurity elements in the solar wind under solar minimum conditions. The relative content of heavy elements in galactic cosmic rays 30–500 MeV/n is similar to values in fluxes from gradual flares during high solar activity. During solar minimum without sunspots, the behavior of Fe/O for different ion energy ranges in plasma flows from coronal holes (CH) and in the solar wind exhibits only minor deviations. At the same time, plasma flows associated with the disturbed frontal CH region can be sources of moderate geomagnetic storms.

scholarly journals Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

2018 ◽  
Vol 4 (1) ◽  
pp. 29-50
Author(s):  
Геннадий Минасянц ◽  
Gennady Minasyants ◽  
Тамара Минасянц ◽  
Tamara Minasyants ◽  
Владимир Томозов ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Cosmic Rays ◽  
Ionization Potential ◽  
Solar Minimum ◽  
Geomagnetic Storms ◽  
Galactic Cosmic Rays ◽  
Ion Fluxes ◽  
Ion Energy ◽  
First Ionization Potential

We report the results of the investigation into plasma physical characteristics at various solar activity manifestations and in periods of their absence. These results have been obtained from quantitative estimates of the relative abundance of Fe/O ions in different energy ranges. Maximum values of the Fe/O ratio is shown to correspond to particle fluxes from impulsive flares for ions with energies <2 MeV/n (the most significant manifestation of the FIP effect). In particle fluxes from gradual flares, the Fe/O value decreases smoothly with ion energy and is noticeably inferior to values of fluxes in impulsive events. We have established that the properties of flares of solar cosmic rays indicate their belonging to a separate subclass in the total population of gradual events. Relying on variations in the abundance of Fe/O ions, we propose an xplanation of the solar plasma behavior during the development of flares of both classes. Magnetic clouds (a separate type of coronal mass ejections (CME)), which have regions of turbulent compression and are sources of strong geomagnetic storms, exhibit a relative composition of Fe ions comparable to the abundance of Fe in ion fluxes from gradual flares. We have found out that the Fe/O value can be used to detect penetration of energetic flare plasma into the CME body at the initial phase of their joint development and to estimate its relative contribution. During solar minimum with complete absence of sunspots, the Fe/O ratio during periods of “quiet” solar wind show absolutely low values of Fe/O=0.004–0.010 in the energy range from 2–5 to 30 MeV/n. This is associated with the manifestation of the cosmic ray anomalous component, which causes an increase in the intensity of ion fluxes with a high first ionization potential, including oxygen (O), and elements with a low first ionization potential (Fe) demonstrate weakening of the fluxes. As for particles with higher energies (Ek>30 MeV/n), the Fe/O increase is due to the decisive influence of galactic cosmic rays on the composition of impurity elements in the solar wind under solar minimum conditions. The relative content of heavy elements in galactic cosmic rays 30–500 MeV/n is similar to values in fluxes from gradual flares during high solar activity. During solar minimum without sunspots, the behavior of Fe/O for different ion energy ranges in plasma flows from coronal holes (CH) and in the solar wind exhibits only minor deviations. At the same time, plasma flows associated with the disturbed frontal CH region can be sources of moderate geomagnetic storms.

scholarly journals Про можливість впливу сонячної активності на врожайність сільськогосподарських культур у Полтавській області

2015 ◽  
pp. 11-21
Author(s):  
П. В. Писаренко ◽  
Я. О. Хлебнікова
Keyword(s):  
Solar Activity ◽  
Correlation Analysis ◽  
Crop Yield ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Vegetation Period ◽  
Maximum Displacement ◽  
Activity Maximum

У статті розглянуто роль сонячної активності уформуванні врожаю різних сільськогосподарськихкультур в агроекологічних умовах Полтавської облас-ті. Проаналізовано дані врожайності сільськогоспо-дарських культур з 25-ти районів Полтавської облас-ті за 47-річний період (з 1966-го року по 2012 рік) тадані середньомісячної сонячної активності (числаВольфа) за аналогічний період. Виявлено, що макси-мум сонячної активності та максимум урожайностіпо всім культурам співпадають у 1989–1991 роках.Встановлено, що зсув по фазі максимуму врожайностіу порівнянні з піком сонячної активності перено-ситься з 1980 року на 1973–1978 роки. Підкреслю-ється, що високі показники врожайності сільськогос-подарських культур можуть спричинятися макси-мумами сонячної активності. Також проведенокореляційний аналіз по кожному з циклів сонячноїактивності між показниками врожайності тасередньомісячними числами Вольфа за веґетаційнийперіод сільськогосподарських культур. The role of solar activity in the formation of yield of different crop in agroecology conditions in Poltava region is considered in this article. Data of crop yield in 25 districts of Poltava region for 47-years period (from 1966 to 2012) and data of average month solar activity (numbers of Wolf) during similar period are analyzed. It has been found out that maximum of solar activity and maximum of yield for all crops are coincided in 1989 and 1990. It has been established that phase of yield maximum displacement in comparison with solar activity maximum are carried from 1980 to 1973-78. It has been stressed that high indices of crop yield can be caused by solar activity maximums. Correlation analysis for each solar activity cycle between yield indices and average month numbers of Wolf during vegetation period is also carried out.

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