It should be possible, for countries in the southern hemisphere, to develop a joint scientific program aimed at studying the properties and behavior of the Earth's ionosphere, based on terrestrial HF power transmitted radiation. The goal of this work is to further acquire knowledge about the physical and electrical properties of the Earth's ionosphere (plasma), which are of particular importance, since they can affect communication and navigation systems and climate changes. Required research instruments for the southern hemisphere measurements and also plasma calculations for Antarctica (EACF) are described. The main facilities research apparatus consists of a high power HF transmitter that can be used to temporarily excite a limited area of the Earth's ionosphere for scientific studies. The question addressed in this work is: What is the maximum energy attained by ionosphere electrons accelerated by electromagnetic wave radiation from a ground based high power HF transmitter?

Es posible que, países meridionales del hemisferio, desarrollen juntos un programa científico dirigido a estudiar las propiedades y el comportamiento de la ionosfera, basado en la radiación de alta potencia de HF transmitida desde la tierra. El objetivo de este trabajo es avanzar en el conocimiento de las propiedades físicas y eléctricas del plasma de la ionosfera de la Tierra, que puede afectar principalmente a los sistemas de comunicación, navegación y cambio climático. Se describen las instalaciones de los instrumentos necesarios para la investigación en el hemisferio sur y también los cálculos del plasma para la Antártica (EACF). Los elementos principales para investigar la ionosfera consisten en un poderoso sistema transmisor de HF, que puede usarse temporalmente para excitar un área limitada de la ionosfera para los estudios científicos. La pregunta es: ¿cuál es la mayor energía alcanzada por electrones de la ionosfera acelerados por radiación electromagnética de un poderoso transmisor de HF?

The possibility of quasi-stable trapping of charged particles of hundreds keV to MeV energy on the frontside Earth magnetosphere is explored in by numerical modeling of the single particle orbits in the geomagnetic field utilizing empirical Tsyganenko magnetic field model. Due to solar wind pressure the remote magnetic field lines on the frontside of the magnetosphere exhibit two minima in the geomagnetic field strength along the field line in high latitudes on the both sides of the equator. These minima may result in stable confinement structures, a kind of radiation belts, in the northern or/and the southern hemispheres, providing energetic particle trapping for times from several minutes to duration of seasonal scale. Simulation of energetic proton orbits passing through the regions of the magnetic field minima with different disturbance level and the Earth's tilt reveals conditions in which these trapped radiation zones could result. It is shown that the existence of the adiabatic confinement zones strongly depends on the seasonal inclination of the Earth's rotation axis. As a result the northern cusp confinement zone appears only in a summer solstice and similarly the southern cusp capture zone appears only in a winter solstice. In equinox time the confinement zones exist in both hemispheres in the disturbed magnetospheric conditions, however, they are less pronounced. The zones are essentially restricted to the sunlit magnetosphere. They form a kind of cusp radiation ring/belt, where a proton drifts with a period of several minutes, conserving its 1st and the 2nd adiabatic invariants. The latitudinal width of the ring is very thin, about 2-5 latitudinal degrees. The proton orbits passing through the off-equatorial field minimum opposite to those cusp belts reveal another interesting effect: a bound of the geomagnetic equatorial plane on the day sector. These and other features of the confinement zones in the two minima off-equatorial magnetic field regions are discussed.

A secondary proton radiation belt can be observed in the equatorial region between the upper atmosphere and the interior edge of the main radiation belt. It is thought that the protons appear there in a result of ionization of energetic neutral hydrogen atoms coming from the internal area of the traditional radiation belt where they were born in charge exchange collisions of the trapped protons with the cold hydrogen of the gecorona. The process of formation of this secondary belt is numerically simulated in this paper assuming this charge exchange-re-ionization mechanism. Standard models of the trapped radiation, of the atmosphere and geocorona were used to simulate the source and the exospheric media. Experimental data were used for charge transfer cross sections. Result of simulation agrees very good with the experimental observation.

The consequences of the March 1991 storm on the Earth's radiation environment are now well known through many in-situ magnetospheric observations. Measurement from the CRRES spacecraft show the sudden formation of a new Helium ion structure deep within the magnetosphere. In that event, two additional new radiation belts were created, one containing large fluxes of 10 MeV electrons, and the other forming a structure containing 30 MeV protons. These sudden space weather phenomena appear to be due the conjunction of the two occurrences: (1) a solar energetic particle (SEP) event arriving in the vicinity of the Earth, and (2) a very intense magnetic storm within the Earth's magnetosphere. Attempts to reproduce the appearance of storm time helium belt by computational modeling are made using a three-dimensional charged particle code (Salammbo code) incorporating Helium ion charge exchange and post-event classical diffusion theory. We have extended the capabilities of the code to Helium ions, and we show that these physical phenomena can also lead to a build-up of a new Helium belt in the 30 MeV range. Detailed modeling predictions of the location of this belt and computed flux levels will be presented and discussed in the context of space weather phenomena in the Earth's magnetosphere.

The ratio of positron/electron fluxes originated in nuclear spallation reactions in the Earth's magnetosphere is considered. It is supposed that positrons as well as electrons are produced in the decay of charged pions (pi±<FONT FACE=Symbol>® m</FONT>± ->e±) born in nuclear collisions of trapped relativistic inner zone protons with the residual atmosphere. These positrons and electrons are captured in the magnetosphere and create positron and electron radiation belts of nuclear origin. The positron/electron trapped magnetospheric fluxes formed with this mechanism are simulated and the resulting computed e+/e- flux ratio ~ 4 appears in agreement with the recent observations. This ratio is significantly different from the ratio ~1 obtained from the primary cosmic ray source through the same mechanism.