Halo Coronal Mass Ejections during Solar Cycle 24: reconstruction of the global scenario and geoeffectiveness

In this study we present a statistical analysis of 53 fast Earth-directed halo CMEs observed by the SOHO/LASCO instrument during the period Jan. 2009-Sep. 2015, and we use this CME sample to test the capabilities of a Sun-to-Earth prediction scheme for CME geoeffectiveness. First, we investigate the CME association with other solar activity features by means of multi-instrument observations of the solar magnetic and plasma properties. Second, using coronagraphic images to derive the CME kinematical properties at 0.1 AU, we propagate the events to 1 AU by means of the WSA-ENLIL+Cone model. Simulation results at Earth are compared with in-situ observations at L1. By applying the pressure balance condition at the magnetopause and a solar wind-Kp index coupling function, we estimate the expected magnetospheric compression and geomagnetic activity level, and compare them with global data records. The analysis indicates that 82% of the CMEs arrived at Earth in the next 4 days. Almost the totality of them compressed the magnetopause below geosynchronous orbits and triggered a geomagnetic storm. Complex sunspot-rich active regions associated with energetic flares result the most favourable configurations from which geoeffective CMEs originate. The analysis of related SEP events shows that 74% of the CMEs associated with major SEPs were geoeffective. Moreover, the SEP production is enhanced in the case of fast and interacting CMEs. In this work we present a first attempt at applying a Sun-to-Earth geoeffectiveness prediction scheme - based on 3D simulations and solar wind-geomagnetic activity coupling functions - to a statistical set of potentially geoeffective halo CMEs. The results of the prediction scheme are in good agreement with geomagnetic activity data records, although further studies performing a fine-tuning of such scheme are needed.Comment: Accepted for publication in the Journal of Space Weather and Space Climate (SWSC

Internal characteristics of magnetic clouds and interplanetary coronal mass ejections

Coronal Mass Ejections (CMEs) are extremely dynamical and huge events in which the solar plasma, initially contained in closed coronal magnetic field lines, is ejected into interplanetary space. When a CME is detected in-situ by a spacecraft located in the interplanetary medium, it is then termed Interplanetary CME (ICME). A set of signatures in plasma and magnetic field data is used to identify it. Among ICMEs, Magnetic Clouds (MCs) represent a special kind of ICME in which the internal magnetic field configuration resembles that of a flux rope (a twisted helical magnetic filament). Using in-situ data provided by instruments onboard the heliospheric mission Ulysses, 40 magnetic clouds have been identified out of 147 ICMEs in the time period between 1992 and 2002. These events constitute the database for this thesis ...thesi

Adaptive Boundary Control Using the Natural Switching Surfaces for Flyback Converters

The derivation and implementation of the natural switching surfaces (NSS) considering certain parametric uncertainties for a flyback converter operating in the boundary conduction mode (BCM) is the main focus of this paper. The NSS with nominal parameters presents many benefits for the control of nonlinear systems; for example, fast transient response under load-changing conditions. However, the performance worsens considerably when the converter actual parameters are different from the ones used in the design process. Therefore, a novel control strategy for NSS considering the effects of parameter uncertainties is proposed. This control law can estimate and adapt the control trajectories in a minimum number of switching cycles to obtain excellent performances even under extreme parameter uncertainties. The analytical derivation of the proposed adaptive switching surfaces is presented together with simulations and experimental results showing adequate performance under different tests, including comparisons with a standard PI controller

Geoeffectiveness of Coronal Mass Ejections in the SOHO era

The main objective of the study is to determine the probability distributions of the geomagnetic Dst index as a function of the coronal mass ejection (CME) and solar flare parameters for the purpose of establishing a probabilistic forecast tool for the geomagnetic storm intensity. Several CME and flare parameters as well as the effect of successive-CME occurrence in changing the probability for a certain range of Dst index values, were examined. The results confirm some of already known relationships between remotely-observed properties of solar eruptive events and geomagnetic storms, namely the importance of initial CME speed, apparent width, source position, and the associated solar flare class. In this paper we quantify these relationships in a form to be used for space weather forecasting in future. The results of the statistical study are employed to construct an empirical statistical model for predicting the probability of the geomagnetic storm intensity based on remote solar observations of CMEs and flares

Clima organizacional y su relación con el desempeño laboral en una empresa distribuidora de aceros en Tarapoto

La investigación tuvo como objetivo determinar la relación entre el clima organizacional y el desempeño laboral en una empresa distribuidora de aceros en Tarapoto. La investigación fue tipo básica, diseño no experimental, transversal y descriptivo correlacional, cuya población fue de 400 trabajadores y la muestra fue de 196. La técnica de recolección de datos fue la encuesta y como instrumento el cuestionario. Los resultados determinaron que el nivel de clima organizacional, fue regular en 50 %, malo en 30 % y bueno en 20 %; el desempeño laboral, fue regular en 62 %, malo en 25 %, y bueno en 13 %. Concluyendo que existe relación significativa entre el clima organizacional y el desempeño laboral en una empresa distribuidora de aceros en Tarapoto, ya que el análisis estadístico de Rho de Spearman fue de 0, 985 (correlación positiva muy alta) y un p valor igual a 0,000 (p-valor ≤ 0.01); además, solo el 97.02 % del clima organizacional influye en el desempeño laboral

Internal Characteristics of Magnetic Clouds and Interplanetary Coronal Mass Ejections

Coronal Mass Ejections (CMEs) are extremely dynamical events in which the solar plasma is ejected into interplanetary space. When a CME is detected in-situ by a spacecraft located in interplanetary space, it is then termed Interplanetary CME (ICME). A set of signatures in plasma and magnetic field data is used to identify it. Magnetic Clouds (MCs) represent a special type of ICMEs in which the magnetic field configuration resembles that of a flux rope. Using in-situ data provided by instruments onboard Ulysses, 40 magnetic clouds have been identified in the time period between 1992 and 2002. These events constitute the database for this thesis. The ionization level of the solar wind plasma serves as a robust tool to characterize the different types of solar wind. Charge states of heavy ions have been used in this work to infer the temperatures in the source region of ICMEs. MCs show increased temperatures with respect to non-cloud ICMEs and surrounding solar wind. By combining these data with a magnetic field model, insights into the internal structure of magnetic clouds are provided. Zones of increased temperatures are found to be confined to the flux rope region. Oxygen ions are found to provide a very good signature of magnetic clouds in the solar wind. Energetic particles can be used to study the ICME topology, internal structure and magnetic connectivity to the Sun. The elemental composition of the energetic particles contained in magnetic clouds has been used to identify the mechanism by which these particles are accelerated. The abundance ratios found are consistent with those for gradual solar energetic particle events (SEPs), meaning that these particles were accelerated by interplanetary shocks. The energetic protons within magnetic clouds are found to be predominantly bidirectional, pointing towards closed magnetic structures, probably with foot points connected connected back to the Sun.Koronale Massenauswürfe (coronal mass ejections, CMEs) sind hochdynamische Ereignisse durch die das Sonnenplasma in den interplanetaren Raum geschleudert wird. Wird ein CME im interplanetaren Raum detektiert, so nennt man ihn Interplanetary CME (ICME). Man benutzt ein Set von Plasma- und Magnetfeldsignaturen um ICMEs zu identifizieren. Magnetische Wolken (magnetic clouds, MCs) gehören zu einer Untergruppe von ICMEs. Ihre Magnetfeldkonfiguration ähnelt der einer magnetischen Flussröhre. Durch die Analyse von Messdaten, die von Instrumenten an Bord der Raumsonde Ulysses zwischen 1992 und 2002 aufgezeichnet wurden, konnten insgesamt 40 magnetische Wolken identifiziert werden. Sie bilden die Basis für diese Arbeit. Die Ionisationszustände des Sonnenwindes dienen als ein robustes Hilfsmittel zur Charakterisierung der verschiedenen Arten von Sonnenwind. Die gemessenen Ladungszustände schwerer Ionen wurden in dieser Arbeit benutzt, um die Temperatur der Quellregion von ICMEs abzuleiten. MCs zeigen höhere Temperaturen, im Vergleich mit den Temperaturen die man innerhalb von ICMEs ohne Wolkenstruktur und im Sonnenwind findet. Diese Daten wurden mit einem Modell für das Magnetfeld verknüpft. Auf diese Weise gewinnt man einen Einblick in die innere Struktur magnetische Wolken. Regionen mit erhöhten Temperaturen sind auf den Bereich der Flussröhre beschränkt. Sauerstoffionen zeigen eine besonders starke Signatur einer magnetischen Wolke im Sonnenwind. Energiereiche Teilchen in ICMEs ermöglichen die Untersuchung ihrer Topologie und inneren Struktur, sowie ihrer magnetischen Verbindung mit der Sonne. Die chemische Zusammensetzung der energiereichen Teilchen in magnetischen Wolken wurde als ein Parameter benutzt, um die Beschleunigungsprozesse zu identifizieren. Die gefundene Elementhäufigkeit stimmt mit der Verteilung in so genannten graduellen SEPs (Solar Energetic Particles) überein, die durch interplanetare Stosswellen beschleunigt werden. Energiereiche Protonen innerhalb MCs zeigen vorwiegend bidirektionale Teilchenverteilungen entlang des Magnetfeldes, woraus man schließen kann, dass MCs geschlossene magnetische Strukturen sind, die wahrscheinlich noch mit der Sonne verbunden

Long Term Ground Based Precipitation Data Analysis: Spatial and Temporal Variability

California is an area of diverse topography and has what many scientists call a Mediterranean climate. Various precipitation patterns exist due to El Niño Southern Oscillation (ENSO) which can cause abnormal precipitation or droughts. As temperature increases mainly due to the increase of CO2 in the atmosphere, it is rapidly changing the climate of not only California but the world. An increase in temperature is leading to droughts in certain areas as other areas are experiencing heavy rainfall/flooding. Droughts in return are providing a foundation for fires harming the ecosystem and nearby population. Various natural hazards can be induced due to the coupling effects from inconsistent precipitation patterns and vice versa. Using wavelets, we were able to identify anomalies of high precipitation and droughts within California\u27s 7 climate divisions using NOAA\u27s hourly precipitation data from rain gauges and compared the results with modeled data, SOI, and PDO. The identification of anomalies can be used to compare and correct remote sensing measurements of precipitation and droughts. Promising results show a possible connection with increasing tropical moisture activity

Competencias digitales y desempeño laboral desde la perspectiva del docente en las IIEE N°100 y N°20391, Huaral, 2021

La presente tesis de maestría tuvo como objetivo central comprender en qué medida se relacionan las competencias digitales y el desempeño laboral de los docentes en dos instituciones educativas pública de la provincia de Huaral durante el año 2021, en el aspecto metodológico la investigación cumplió los requerimientos para ser clasificada como básica, siguió un diseño de investigación de tipo no experimental correlacional transversal. Respecto a la población de investigación la conformaron 80 docentes de dos instituciones públicas. Para efectos de la recolección de información la técnica asumida fue la encuesta mientras que los instrumentos utilizados fueron el Perfil de las competencias docentes digitales de Rangel (2013) y el Cuestionario de autopercepción sobre desempeño docente de Pérez (2021). A fin de contrastar la hipótesis se utilizó la prueba estadística inferencial Rho de Spearman, para el caso de la hipótesis general se obtuvo un valor sig igual a 0,000 con un coeficiente de correlación de 0,577 lo que conllevó a confirmar la hipótesis llegando a concluirse que existe una relación estadística significativa entre las competencias digitales y el desempeño laboral, dicha correlación fue moderada. Asimismo los resultados de las hipótesis específicas demostraron que las dimensiones tecnológica, informacional y pedagógica de las competencias digitales se encuentran relacionadas con el desempeño laboral docente