Phase Of Solar Activity Cycle Research Articles

The effect of geomagnetic storms on aircraft accidents between the years 1919–2023 in civil aviation

Detailed research on the effect of geomagnetic storms (GSs) on air crash investigations, which is a very important space weather event and could be the main reason for most aircraft accidents, especially unexplained accidents, has not been done by this time. In this study, we investigated the effect of GSs depending on seasonal changes, solar activity, and geomagnetic activity (GA) over 115 years of aircraft accidents from the decreasing phase of the Solar Cycle (SC) 15 to the increasing phase of SC 25. In our analysis, the accident rates of 1959 air crash events correspond to 68 %, 22 %, 8 %, and 2 % due to mechanical and pilotage reasons, unknown reasons, bad weather conditions, and turbulence that might be related to GSs are obtained for latitudes between ± 10⁰ ≤ φ ≤ ±90⁰ in the northern and southern hemispheres. The MATLAB R2018a Programming Language is used to determine and draw all data in our statistical analyses. Nevertheless, we reconstructed the GA indices such as Dst, Kp, Ap, aa, and am for 1919–2023 by using the Autoregressive Integrated Moving Average (ARIMA) Forecasting Model for years without observations and therefore missing data. The first important result is that the number of aircraft accidents increased in the decreasing phases of solar activity cycles (SACs) depending on the effective structure of the coronal holes rather than increasing phases. The second important result is that the highest number of accidents occurred in the equinoxes in March and September (and mostly at the beginning of October) while the lower number of accidents was seen in the solstices such as June and December. The third important result is that the rate of accidents depends on how many storms were seen in the decreasing phase of SACs. The SC maximum intensity value that reaches the higher number, or even the duration of the SC will not affect aircraft accidents directly. The GA indices do not follow a regular pattern according to the SC shows that we should look at the geomagnetic structure of the intensity of three elements of a magnetic field of Earth as D (Declination), H (Horizontal), and z (Vertical), and therefore their intensities.

Hysteresis effect between geomagnetic activity indices (Ap, Dst) and interplanetary medium parameters in solar activity cycles 21–24

We have studied the relationship of geomagnetic activity indices (Ap, Dst) on time intervals, equal to solar cycles (∼11 years), with solar activity indicators and heliospheric parameters. It is shown that the plots of the Ap and Dst indices versus solar activity indicators, as well as versus heliospheric parameters, i.e. solar wind and IMF parameters in the ascending and descending phases of solar activity cycles 21–24 do not coincide, which is indicative of the hysteresis phenomenon. The Ap and Dst indices form hysteresis loops with all parameters we analyze during cycles 21–24. The shape and area of the hysteresis loops, as well as the direction of rotation, clockwise or counterclockwise, depend significantly on indicators of solar activity, heliospheric parameters and change from cycle to cycle. We have found a tendency for the extension and area of the hysteresis loops to decrease from cycle 21 to cycle 24. Analysis of the variability in the shape and size of the hysteresis loops formed by the Ap and Dst indices with solar indicators and heliospheric parameters gives reason to believe that the obtained loops reflect the long-term evolution of the solar wind energy flux, which determines global geomagnetic activity and the magnetospheric ring current intensity in the ascending and descending phases of solar activity cycles 21‒24.

Эффект гистерезиса между индексами геомагнитной активности (Ap, Dst) и параметрами межпланетной среды в 21-24 циклах солнечной активности

We have studied the relationship of geomagnetic activity indices (Ap, Dst) on time intervals, equal to solar cycles (∼11 years), with solar activity indicators and heliospheric parameters. It is shown that the plots of the Ap and Dst indices versus solar activity indicators, as well as versus heliospheric parameters, i.e. solar wind and IMF parameters in the ascending and descending phases of solar activity cycles 21–24 do not coincide, which is indicative of the hysteresis phenomenon. The Ap and Dst indices form hysteresis loops with all parameters we analyze during cycles 21–24. The shape and area of the hysteresis loops, as well as the direction of rotation, clockwise or counterclockwise, depend significantly on indicators of solar activity, heliospheric parameters and change from cycle to cycle. We have found a tendency for the extension and area of the hysteresis loops to decrease from cycle 21 to cycle 24. Analysis of the variability in the shape and size of the hysteresis loops formed by the Ap and Dst indices with solar indicators and heliospheric parameters gives reason to believe that the obtained loops reflect the long-term evolution of the solar wind energy flux, which determines global geomagnetic activity and the magnetospheric ring current intensity in the ascending and descending phases of solar activity cycles 21‒24.

The Magnetic Storm of August 25–26, 2018: Dayside High Latitude Geomagnetic Variations and Pulsations

The features of daytime high latitude geomagnetic disturbances and geomagnetic pulsations during the recent strong magnetic storm on August 25–26, 2018, which occurred at the end of the decline phase of the 24th solar activity cycle with a very low level of solar flare activity, are considered. As a rule, during this phase of the solar activity cycle, magnetic storms are caused by high-speed solar wind flows from coronal holes; however, the magnetic storms during the decay of the 24th cycle were caused by coronal mass ejections (CMEs). It was shown that, despite very weak disturbances on the Sun and a low solar wind speed, a rather strong magnetic storm occurred in the Earth’s magnetosphere in August 2018 (Dst = –171 nT). The storm SC with a slight (~25 nT) jump in the Dst index caused quite intense daytime geomagnetic pulsations ipcl at the latitudes of the possible position of the daytime polar cusp. A feature of the recovery phase of this storm was the development of a magnetosphere substorm on a global scale, i.e., the appearance of a negative magnetic bay recorded simultaneously in the auroral night sector and in the polar latitudes of the day sector. A possible interpretation is considered.

Calculation of Radiation Loads in a Space Station Compartment with Additional Protection of High-Pressure Polyethylene

The paper presents the results of the calculation of cosmic ionizing radiation doses for conditions that simulate ISS crew quarters outfitted with additional protection in the form of a “protective shutter” kit used in the Matryoshka-R experiment; the kit is filled with high-pressure polyethylene instead of regular means of cosmonaut personal hygiene (wet wipes and towels). The calculation was performed using the ray tracing method, which was previously verified using the experimental data on the dose loads in the space station sections. The protective shutter kit has a thickness of 10 cm and covers the exterior wall of the crew quarters; its volume is filled with high-pressure polyethylene. The calculation is performed for the locations of experimental dosimetric assemblies for typical ISS orbits in the phase of minimum and maximum solar activity. The effect from the use of the additional protection (AP) in the ISS crew quarters in terms of the equivalent dose varies between 22 and 60% depending on the orbital altitude, phase of solar activity cycle, and initial conditions of protection. The results indicate a higher efficiency of the additional protection of polyethylene in comparison with water-containing materials. This AP from cosmic radiation has the potential to be used in long-term and long-range spaceflights.

Analysis of Temporal Variations in Failed Missile Launches in the Soviet Union (Russia) and the United States

Temporal variations in the relative number of failed rocket launches in Russia (Soviet Union) and the United States have been compared to reveal that these variations are antipersistent. The accident rates of rocket and space equipment launches have been analyzed as a function of the level and phase of solar activity cycle. The relative number of failed launches in Russia (Soviet Union) and the United States for the growth phase of solar activity has been shown to exceed the number for the phase of solar activity decline, although no clear correlation between solar activity and the number of failed launches has been detected.

English

It has been established that Coronal Mass Ejections (CMEs) follow the phase of solar activity cycle. CMEs are known to be the major cause of geomagnetic storms which have devastating effects on earth atmosphere. Predicting their arrival times has been a major issue in space weather forecast. Influence of the phases solar activity cycle 23 on CMEs transit time were investigated using fast CMEs data with initial speed ≥ 900 kms-1 that were associated with intense geomagnetic storm obtained from Large Angle Spectrometric Coronagraph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO) for solar cycle 23. Empirical Coronal Mass Ejections Arrival (ECA) model equations of Ojih-Okeke modified model, Gopalswamy 2000 model (G2000), Gopalswamy 2001 model (G2001), and Vrsnak and Gopalswamy 2002 model (VG2002) were applied to the data points. Scatter plots of CMEs transit time as function of CMEs initial speed and solar wind speed were generated. Linear correlation coefficients were obtained. The significance of the correlation was tested at 0.05 level of significant. Linear correlation coefficients obtained for solar maximum period of solar cycle 23 for Ojih-Okeke model, VG2002 model, G2001 model and G2000 model were -0.63, -0.82, -0.78 and -0.79 respectively and those obtained for declining phase of solar cycle 23 were -0.93, -0.80, -0.80 and -0.86 respectively. There is no significant difference between the correlations obtained for solar maximum phase and the declining phase of solar cycle 23. The findings depict that phases of solar activity cycle has no significant influence on CMEs transit time. Key words: Coronal mass ejections, solar activity cycle, transit time, phase, geomagnetic storm. &nbsp

Launch malfunctions and space weather factors

The space rocket launch malfunctions frequency has been analyzed depending on the level and the phase of solar activity cycle and the season of year. Comparative analysis of the temporal variations of the relative number of failed launches in Russian Federation and the United states has been conducted. It was stated that those variations were anti-persistent. It was shown that for the phase of rise of solar activity the relative amount of failed launches both in Russian Federation and the United states exceeds the similar values for that of its decline. However, an explicit dependence between solar activity and the amount of failed launches is not observed.

Temporal variations of different solar activity indices through the solar cycles 21-23

Here, we compare the sunspot counts and the number of sunspot groups (SGs) with variations of total solar irradiance (TSI), magnetic activity, Ca II K-flux, faculae and plage areas. We applied a time series method for extracting the data over the descending phases of solar activity cycles (SACs) 21, 22 and 23, and the ascending phases 22 and 23. Our results suggest that there is a strong correlation between solar activity indices and the changes in small (A, B, C and H-modified Zurich Classification) and large (D, E and F) SGs. This somewhat unexpected finding suggests that plage regions substantially decreased in spite of the higher number of large SGs in SAC 23 while the Ca II K-flux did not decrease by a large amount nor was it comparable with SAC 22 and relates with C and DEF type SGs. In addition to this, the increase of facular areas which are influenced by large SGs, caused a small percentage decrease in TSI while the decrement of plage areas triggered a higher decrease in the magnetic field flux. Our results thus reveal the potential of such a detailed comparison of the SG analysis with solar activity indices for better understanding and predicting future trends in the SACs.

Distribution of strong and super flares by phases of solar activity cycles

The phase distribution of all strong X-ray flares from 1976 to 2013 and the flares in the current 24th cycle have been investigated. It is concluded that, until around 2019, mid-level M-class flares and strong (up to X8 class) flares can be expected. Stronger flares may also occur. Superflares like the Carrington event are unlikely.

Visibility-Graph Analysis of the Solar Wind Velocity

We analyze in situ measurements of solar wind velocity obtained by Advanced Composition Explorer (ACE) spacecraft and Helios spacecraft during the years 1998-2012 and 1975-1983 respectively. The data belong to mainly solar cycle 23 (1996-2008) and solar cycle 21 (1976-1986) respectively. We use Directed Horizontal Visibility graph (DHVg) algorithm and estimate a graph functional, namely, the degree distance (D) as the Kullback-Leibler divergence (KLD) argument to understand time irreversibility of solar wind time series. We estimate this degree distance irreversibility parameter for these time series at different phases of solar activity cycle. Irreversibility parameter is first established for known dynamical data and then applied for solar wind velocity time series. It is observed that irreversibility in solar wind velocity fluctuations show similar behaviour at 0.3 AU (Helios data) and 1 AU (ACE data). Moreover it changes over the different phases of solar activity cycle.

Corotating interaction regions during the recent solar minimum: The power and limitations of global MHD modeling

The declining phase of solar activity cycle 23 has provided an unprecedented opportunity to study the evolution and properties of corotating interaction regions (CIRs) during unique and relatively steady conditions. The absence of significant transient activity has allowed modelers to test ambient solar wind models, but has also challenged them to reproduce structure that was qualitatively different than had been observed previously (at least within the space era). In this study, we present and analyze global magnetohydrodynamic (MHD) solutions of the inner heliosphere (from 1RS to 1AU) for several intervals defined as part of a Center for Integrated Space weather Modeling (CISM) interdisciplinary campaign study, and, in particular, Carrington rotation 2060. We compare in situ measurements from ACE and STEREO A and B with the model results to illustrate both the capabilities and limitations of current numerical techniques. We show that, overall, the models do capture the essential structural features of the solar wind for specific time periods; however, there are times when the models and observations diverge. We describe, and, to some extent assess the sources of error in the modeling chain from the input photospheric magnetograms to the numerical schemes used to propagate structure through the heliosphere, and speculate on how they may be resolved, or at least mitigated in the future.

Solar wind turbulence during the solar cycle deduced from Galileo coronal radio-sounding experiments

Seven coronal radio-sounding campaigns were carried out during the active lifetime of the Galileo spacecraft in the years 1994–2002. The observational data analyzed in the present work are S-band frequency fluctuation measurements recorded during the solar conjunctions at different phases of solar activity cycle #23, specifically: periods near solar maximum (three conjunctions), near solar minimum (three conjunctions) and during the ascending phase (one conjunction). These data are all applicable to low heliographic latitudes, i.e. to the slow solar wind. The rms frequency fluctuation and power-law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The turbulence power spectrum tends to be flatter inside ca. 20 solar radii during all phases of the solar cycle. This coincides with a transition in the flow from the inner acceleration region to the outer region of constant velocity. The radial falloff rate and absolute level of the rms frequency fluctuation are essentially invariant over the solar cycle.

Consequences of the force‐free model of magnetic clouds for their heliospheric evolution

We examine the implications of the widely used, force‐free, constant‐αflux rope model of interplanetary magnetic clouds for the evolution of these mesoscale (fraction 1 AU) structures in the heliosphere, with special emphasis on the inner (≤1 AU) heliosphere. We employ primarily events observed by the Helios 1 and 2 probes between 0.3 and 1 AU in the ascending and maximum phases of solar cycle 21 and by Wind at 1 AU in a similar phase of solar activity cycle. We supplement these data by observations from other spacecraft (e.g., Voyagers 1 and 2, Pioneers 10 and 11, and others). Our data set consists of 130 events. We explore three different approaches. In the first, we work with ensemble averages, binning the results into radial segments of width 0.1 AU in the range 0.3 ≤rh≤ 1 AU. Doing this, we find that in the inner heliosphere the modeled average central axial field strength, 〈B0〉, varies with heliospheric distancerhas 〈B0〉 [nT] = 18.1 ·rh−1.64[AU], and the average diameter increases quasi‐linearly as 〈D〉 [AU] = 0.23rh1.14. The orientation of the axis of the underlying magnetic flux tube in our data set is generally found to lie along the east–west direction and in the ecliptic plane at all values ofrh, but there is considerable scatter about these average directions. In the second, we monitor the evolution of magnetic clouds in snapshot fashion, using seven spacecraft alignments. The results are in broad agreement with the statistics reported under step 1. In the final approach, we obtain the functional dependence ofB0andDpredicted by an analytic expression for a freely expanding Lundquist flux tube. We findDto vary linearly withrh, broadly similar to that obtained under approach 1. The maximum field strength scales asrh−2compared to arh−1.3dependence obtained from statistics. We compare our findings with those of Bothmer and Schwenn (1998), who used a different methodology. The results obtained form a good background to the forthcoming Solar Terrestrial Relations Observatory (STEREO) and Sentinels missions and to multispacecraft studies of magnetic clouds.

Primary Study About the Relationships Between Coronal Holes' Parameters and the Correlative Geomagnetic Disturbances

在提取冕洞特征参数的基础上,利用1996年到2005年8月近十年来对地磁扰动有影响的356个冕洞事例,定量分析了冕洞特征参数(包括冕洞的面积比、经纬度跨度等)与冕洞高速流特征、重现型地磁扰动特征(包括扰动大小和持续时间等)之间的相关性,研究发现,从引起地磁扰动的冕洞在整个太阳活动周的分布来看,在地磁扰动峰年中冕洞影响同样具有重要的贡献;冕洞高速流太阳风速度与地磁扰动强度之间存在较强的相关性,而高速流中太阳风速度与冕洞面积比关系不大,与冕洞亮度存在一定相关性;冕洞的经度跨度与地磁扰动持续时间存在很强的正相关性.

Ulysses observations of very different heliospheric structure during the declining phase of solar activity cycle 23

This study examines the most recent observations from the solar wind experiment (SWOOPS) on the Ulysses spacecraft. In contrast to observations over the same locations in the declining phase of the previous solar activity cycle, these data show a more complicated heliospheric structure. Around the start of 2003, a band of slow solar wind resided at ∼20°–25°N latitude at all helio‐longitudes. Subsequently, Ulysses failed to observe a well‐organized corotating stream structure as it headed southward from the ecliptic plane, even though, in the previous solar cycle, Ulysses observed a regularly structured stream pattern. These observations show that the three‐dimensional structure of the heliosphere can differ significantly from one solar cycle to the next. Finally, we show that the solar wind dynamic pressure has been relatively stable throughout 2005, indicating that the termination shock distance will also likely be relatively stable throughout 2006.

Latitudinal Distribution of the Coronal Bright Points at Solar Minimum and the Rising Phase of Solar Activity Cycle 23

We show that the latitudinal distribution of the coronal bright points (BPs) changes between the solar minimum and the rising phase of solar cycle 23. In 1996, the number of BPs peaks near the disk center. In 1998, the distribution shows bands of increased BPs' number at the ARs' latitudes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Tracing the “Acoustic” Solar Cycle: A Direct Comparison of BiSON and GOLF Low‐lp‐Mode Variations

We present a detailed, comparative study of low angular degree solar p-mode variations extracted by analyses of two sets of observational data. These were collected by the ground-based Birmingham Solar-Oscillations Network (BiSON) and the Global Oscillations at Low Frequency (GOLF) instrument on board the ESA/NASA SOHO satellite. The ~5.5 yr period analyzed covers the complete rising phase of solar activity cycle 23 (1996-2002). We find an excellent level of agreement in the uncovered variations, indicating that the two data sets are highly correlated and dominated by the same mode realization noise (the signature of the stochastic forcing of the resonances). The results lend further support to the surmise that changes in damping alone may account for observed variations in mode power and damping. While significant variations in peak asymmetry are uncovered in the near-continuous GOLF set, a similar analysis of the BiSON database yields a null result. This reflects the deleterious impact of its ground-based window function on the precision with which the asymmetry can be determined. As such we are unable to rule out the possibility that variations of magnitude similar to those in GOLF may be present in the BiSON observations.

PERIODICITY IN DAILY VARIATION OF COSMIC RAY INTENSITY AS AN EFFECT OF SOLAR POLOIDAL MAGNETIC FIELD ORIENTATION

A detailed analysis of the Deep River neutron monitor (NM) data for four different phases of solar activity cycle and for four groups of days chosen according to their different geomagnetic conditions is being carried out. It is found that the 60 quiet day (QD) in a year serve a better purpose for investigating the short/long term variation in cosmic ray (CR) intensity. Furthermore, data has been harmonically analysed for the period 1964–95 to investigate the effect of solar poloidal magnetic field (SPMF) orientation in daily variation (diurnal/semi-diurnal) of CR on geomagnetically QD. The phase of the diurnal and semi-diurnal anisotropy vectors on QD has shown a significant shift to early hours when the SPMF in the northern hemisphere (NH) is positive during the periods 1971–79 and 1992–95 as compared to that during the periods 1964–70 and 1981–90 when the SPMF in NH is negative, showing a periodic nature of daily variation in CR intensity with SPMF.

Solar Wind Speed and Expansion Rate of the Coronal Magnetic Field in Solar Maximum and Minimum Phases

Relationships between solar wind speed and expansion rate of the coronal magnetic field have been studied mainly by in-ecliptic observations of artificial satellites and some off-ecliptic data by Ulysses. In this paper, we use the solar wind speed estimated by interplanetary scintillation (IPS) observations in the whole heliosphere. Two synoptic maps of SWS estimated by IPS observations are constructed for two Carrington rotations CR 1830 and 1901; CR 1830 starting on the 11th of June, 1990 is in the maximum phase of solar activity cycle and CR 1901 starting on the 29th of September, 1995 is in the minimum phase. Each of the maps consist of 64800 (360×180) data points. Similar synoptic maps of expansion rate of the coronal magnetic field (RBR) calculated by the so-called ‘potential model’ are also constructed under a radial field assumption for CR 1830 and CR1901. Highly significant correlation (r=−0.66) is found between the SWS and the RBR during CR1901 in the solar minimum phase; that is, high-speed winds emanate from photospheric areas corresponding to low expansion rate of the coronal magnetic field and low speed winds emanate from photospheric areas of high expansion rate. A similar result is found during CR 1830 in solar maximum phase, though the correlation is relatively low (r=−0.29). The correlation is improved when both the data during CR 1830 and CR 1901 are used together; the correlation coefficient becomes −0.67 in this case. These results suggest that the correlation analysis between the SWS and the RBR can be applied to estimate the solar wind speed from the expansion rate of the coronal magnetic field, though the correlation between them may depend on the solar activity cycle. We need further study of correlation analysis for the entire solar cycle to get an accurate empirical equation for the estimation of solar wind speed. If the solar wind speed is estimated successfully by an empirical equation, it can be used as an initial condition of a solar wind model for space weather forecasts.