The Statistical Analysis of Characteristics of Coronal Mass Ejection During the Descending Phase of Solar Cycle 23 and 24

The characteristics of CMEs we studied are angular width, linear speed, and acceleration for all categories of CMEs such as narrow (W ≤20°), intermediate (20°< W<200°), wide (W ≥ 200°) and linear speed <500 km/s during the descending phase of solar cycle 23 and 24 and compared them. We have found that there are 1951 narrow CMEs during solar cycle 23 that is 1.9 times greater than in solar cycle 24 (1047). On the other side, the number of intermediate CMEs during solar cycle 24 (1571) is 1.14 times more than solar cycle 23 (1162). We observed no noticeable difference between the number of wide CMEs of solar cycle 23 (29) and 24 (36). The angular width of CMEs during the descending phase of solar cycle 23 and solar cycle 24, predominately distributed around 100-600. The fascinating result is that the angular width distributions for the descending phase of solar cycles are approximately identical. On comparing the results of linear speed of both solar cycle, we can say that, (i) 93.7% (1729) and 87.7% (908) of narrow CMEs, (ii) 97% (1328) and 94% (1479) of intermediate CMEs and (iii) 44% (13) and 42% (15) of wide CMEs have speed of <500 km s-1, respectively. Mostly the fractions of narrow and intermediate CMEs decline sharply at the speeds greater than 500 km s-1. The maximum speed observed during the 23rd cycle is 1994 km/s (wide CME) and the 24th cycle is 3163 km/s (wide CME) respectively. It was noticed that the speed of the 24th solar cycle CME is higher than the 23rd solar cycle CME. The major fraction of CMEs has acceleration in the range of -20 to 20 km s-2, all types of CMEs. The narrow and intermediate CMEs mostly show acceleration while wide CMEs show deceleration.

Kinematics of coronal mass ejections in the LASCO field of view

In this paper we present a statistical study of the kinematics of 28894 coronal mass ejections (CMEs) recorded by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory spacecraft from 1996 until mid-2017. The initial acceleration phase is characterized by a rapid increase in CME velocity just after eruption in the inner corona. This phase is followed by a non-significant residual acceleration (deceleration) characterized by an almost constant speed of CMEs. We demonstrate that the initial acceleration is in the range 0.24–2616 m s−2 with median (average) value of 57 m s−2 (34 m s−2) and it takes place up to a distance of about 28 RSUN with median (average) value of 7.8 RSUN (6 RSUN). Additionally, the initial acceleration is significant in the case of fast CMEs (V > 900 km s−1), where the median (average) values are about 295 m s−2 (251 m s−2), respectively, and much weaker in the case of slow CMEs (V < 250 km s−1), where the median (average) values are about 18 m s−2 (17 m s−2), respectively. We note that the significant driving force (Lorentz force) can operate up to a distance of 6 RSUN from the Sun during the first 2 hours of propagation. We found a significant anti-correlation between the initial acceleration magnitude and the acceleration duration, whereas the residual acceleration covers a range from −1224 to 0 m s−2 with a median (average) value of −34 m s−2 (−17 m s−2). One intriguing finding is that the residual acceleration is much smaller during the 24th cycle in comparison to the 23rd cycle of solar activity. Our study has also revealed that the considered parameters, initial acceleration (ACCINI), residual acceleration (ACCRES), maximum velocity (VMAX), and time at maximum velocity (TimeMAX) mostly follow solar cycles and the intensities of the individual cycle.

A routine activity perspective on online victimisation

Purpose – The purpose of this study is to test a comprehensive routine activity framework on three types of online victimization. Prior research has utilized routine activity theory to explain varied online forms of victimization, but most have focused on its person-based forms. The present study, therefore, expands upon this research to examine the effects of online exposure, online target suitability and online guardianship upon phishing, hacking and malware infection victimization. Design/methodology/approach – Secondary data from the 23rd Cycle of the Canadian GSS were used to address the study’s research questions using binary logistic regression analyses. Findings – Particular online behaviors were consistently and positively related to all three types of online victimization, including booking/making reservations, social networking and having one’s information posted online. Other online routines exhibited unique effects on online victimization risk. Originality/value – In support of the theory, the results suggest that online exposure and target suitability increase risks for phishing, hacking and malware victimization. Online guardianship was also positively related to victimization, a finding that runs counter to theoretical expectations.

Study on Corrosion Behavior of Hot Dip Coatings in Wet-Dry Cyclic Conditions

The corrosion of fasteners in ballast tank is much serious, due to the wet-dry corrosive conditions. Now most fasteners are protected by zinc-aluminium coating. In order to evaluate the anticorrosion performance of hot dip Galvanized (GI), Galfan (GF) and Galvalume (GL) coated fasteners in wet-dry cyclic conditions, the corrosion behavior of these coatings in 1h wet and 7h drying condition were investigated by electrochemical impedance spectroscopy technology. The corrosion rate of GI coating in drying condition is much faster than that in wet condition before 23rd cycle, after that time the corrosion rate in sea water is faster than that in drying condition, however the corrosion rate of GF coatings in drying condition is much slower than that in wet condition, and for GL coating, the polarization resistance is both than 104Ω•cm2, whether it is immersed in seawater or in drying condition, which suggests it has better anticorrosion performance. The corrosion rate of the GI, GF and GL coating is 30µm per year, 1.5µm per year and 1.3µm per year respectively and corrosion resistance of GL and GF is therefore twenty two and twenty times as that of GI.

On the extended 23rd solar cycle

An explanation of the mystery of the extended 23rd solar cycle duration about 13 years in the frame of non-linear regime of the αΩ- dynamo model is proposed. The calculated dynamo-period of the solar cycle, T, depends (in the inverse proportion) on the intensity of the α- effect in the solar convection zone (SCZ). As well, the intensity of the α- effect in non-linear regime depends (also in the inverse proportion) on the value of toroidal magnetic field, BT (magnetic alpha-quenching). Thus, the calculated period is in direct proportion to the value of toroidal magnetic field: the stronger toroidal field BT in certain cycle, the longer dynamo-period T of this cycle. Since the toroidal field is hidden in the deep layers of the SCZ, it is necessary to know some other magnetic experimental evidence that reflects something like information about inner toroidal field. In this connection we allow for that the strong toroidal field is transported by magnetic buoyancy to the solar surface and produces here the sunspots, so they carry indirect information on BT. In this connection we took into account up-to-date observed data on the essential increase of the averaged annual module of the magnetic field of the large-scale sunspots, Bsp, in the 23rd cycle; and then we made calculation of the alpha-quenching which depends on these referred data. It is important to know only relative variations of magnetic index Bsp for calculation of the dynamo-period variation. Our estimations showed that the average solar period, which is about 11 years, must increase by a factor of 1,2; so the calculated 23rd cycle dynamo-period would be about 13 years.

The heliosphere mass variations: 1996–2006

The variations of the global mass of heliosphere in the 23rd cycle of the solar activity are described. The results are derived from solar corona observations and from ‘in situ’ measurements made by the space probes SOHO, VOYAGER2, ACE, WIND, and ULYSSES. It has been revealed that though the total mass of corona fluctuates during the solar activity cycle approximately in a ratio of 1 : 3, the specific mass flow (q) in the solar wind does not change in the ecliptic plane. In the polar regions the q decreases during the minimum in a third of the original value and the velocity of expansion is roughly double. These findings are valid for the 23rd solar cycle.