A computational model for geomagnetically trapped particle shells and kinematic parameters Technical report, Oct. 1965 - Jun. 1966

Computer program to calculate geomagnetically trapped particle shell model, drift rate, and bounce path

New Toroidal Beam Antennas for WLAN Communications

[Abstract] The design of a number of new antennas that radiate linearly polarized toroidal beams is described. The developed procedures are based on the use of a method of moments commercial software tool. Several numerical examples, working at WLAN communication frequencies, are derived and analyzed. Two experimental prototypes validate the numerical result

Synthesis of Multi-Radial Line Antenna for HIPERLAN

This paper is a postprint of a paper submitted to and accepted for publication in journal Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library"[Abstract] We present a new antenna concept - the multi-radial travelling wave line antenna - that achieves a broadband conical radiation pattern suitable for use in multiple C-band wireless computer networks

Perturbation of the Phases of Taylor Field Samples in the Synthesis of Linear and Circular Array Antennas

[Abstract] Antenna design specifications do not usually restrict the phase of the radiated field. Antenna synthesis techniques generally exploit this freedom only indirectly, but direct phase perturbation can be fruitful

Solar variability effects on climate

One of the key tasks in climate research at the present time is to separate anthropogenic effects from natural change. Solar variability is one possible cause of natural change in addition to other external phenomena such as volcanic eruptions and, on a long-term scale, orbital changes and celestial body impacts. The topic of "sun-weather relationships" has followed a long and tortuous history of scientific speculations and controversy since the continuous observation of sunspots began in the 17th century. It was not until recently that more systematic studies with long-term data bases of meteorological, climatological and solar parameters led to an increasing, statistically robust, body of evidence for a causal connection between some manifestations of solar variability and changes in the troposphere and the climate system. While of planetary' scale, the strength and sign of pertinent correlations have distinct geographic, seasonal and other temporal characteristics. Most likely, several trigger mechanisms are at work simultaneously, but their relative importance may depend on the time-scale envisaged and on competing processes such as volcanic eruptions. In this paper we will summarize the most frequently formulated criticisms, review the most recent results on relevant solar variability effects at the 11-year, secular, and short-term time scales, and discuss proposed mechanisms such as enhanced Hadley circulation, charged particle ionization effects on clear-air conductivity, and electric field effects on the microphysics of cloud formation.En la actualidad, una tarea clave de la investigación climática es la de separar los efectos antropogénicos de los cambios naturales. La variabilidad del sol es una posible causa del cambio natural junto con otros posibles fenómenos de orden externo como por ejemplo las erupciones volcánicas y en escalas de tiempo mas largas cambios orbitales y el impacto de cuerpos celestes. El tema "relación sol-clima" ha seguido una larga y tortuosa historia de especulación científica y controversias desde que en el siglo 17 se empezaron a observar en forma continua las manchas solares. Recientemente, sobre la base de estudios más sistemáticos y bases de datos de períodos largos de parámetros meteorológicos, climatológicos y solares se dispone de un cuerpo de evidencias amplio y estadísticamente robusto de la conexión causal entre algunas manifestaciones de la variabilidad solar y cambios en la troposfera y el clima. En la escala planetaria, la intensidad y signo de las correlaciones poseen distintas características geográficas, estacionales y otras temporales. Muy probablemente, distintos mecanismos de "trigger" operan simultáneamente, pero su importancia relativa puede depender de la escala de tiempo considerada y de procesos competitivos como las erupciones volcánicas. En este trabajo, haremos un resumen de las críticas mas frecuentes, veremos los resultados recientes más relevantes de los efectos de la variabilidad solar de 11 años, secular, y escala de tiempo corta; y discutiremos mecanismos propuestos como la circulación de Hadley ampliada, efectos ionizantes de partículas cargadas sobre la conductividad del aire limpio, y efectos del campo eléctrico en la microfísica formación de nubes.Material digitalizado en SEDICI gracias a la colaboración de la Facultad de Ciencias Astronómicas y Geofísicas (UNLP).Asociación Argentina de Geofísicos y Geodesta

Prompt energization of relativistic and highly relativistic electrons during a substorm interval: Van Allen Probes observations

Abstract On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy source for subsequent radiation belt enhancements. Highly relativistic (\u3e2 MeV) electron fluxes increased immediately at L* ~ 4.5 and 4.5 MeV flux increased \u3e90 times at L* = 4 over 5 h. Although plasmasphere expansion brings the enhanced radiation belt multi-MeV fluxes inside the plasmasphere several hours postsubstorm, we localize their prompt reenergization during the event to regions outside the plasmasphere. Key Points Substorm dynamics are important for highly relativistic electron energization Cold plasma preconditioning is significant for rapid relativistic energization Relativistic / highly relativistic electron energization can occur in \u3c 5 hrs