Ciencias del Geoespacio y Astronomía
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Item Open Access Seis conferencias sobre el campo geomagnético de la tierra y los rayos cósmicos por el Dr. Scott E. Forbush(Instituto Geofísico del Perú, 1959) Instituto Geofísico de HuancayoEl Instituto Geofísico de Huancayo, entidad científica peruana, presenta al público científico de habla hispana la traducción de seis conferencias dictadas en la Universidad Nacional Mayor de San Marcos y otras instituciones docentes del Perú en setiembre y octubre de 1959 por el eminente Dr. Scott E. Forbush, investigador del Departamento Terrestre de la Institución Carnegie de Washington que dirige el famoso Dr. Merle A. Tuve.Item Open Access A new phase measuring technique for the minitrack satellite tracking system(Instituto Geofísico del Perú, 1960) Woodman Pollitt, Ronald FranciscoA New Phase Measuring Technique has been developed as a solution to some of the present limitation of Minitrack Satellite Tracking System. Two main problems are solved, one concerned with the processing of the information and the other, with the sensitivity of the system. The present Minitrack is not a real time system. The output information has to be solved from ambiguity, smoothed, and corrected at a centralized computer location with a resultant time delay. The output of the mew system is real time, free from ambiguity, and fully corrected. It will be used to plot the satellite position in X and Y coordinates and could be used to drive telemetry, antennas or optical cameras. Its digital output is a five decimal digit directional cosine number ready for transmission to the centralized computer for orbital computation. The present Minitrack sensitivity is determined by a passive 10 cps bandwidth filter. The bandwidth is the narrowest bandwidth with linear phase vs frequency characteristics for a maximun differential doppler shift of 2 cps (approximately 2 ° per second angular rate).Item Open Access A phase-locked phase filter for the minitrack system(National Aeronautics and Space Administration, 1962-09) Woodman Pollitt, Ronald FranciscoA variable-bandwidth filter has been designed and built to narrow the postdetection bandwidth of the Minitrack satellite tracking system. It is based on phase-lock techniques. Al its narrowest bandwidth, 0.03 cps, the phase peak-topeak noise deviations are reduced to ± 1.5 percent of a wavelength for a signal strength of -140 dbm coming into the receiver "front ends". The filter introduces no phase shift or time delay regardless of the signal phase rate.Item Open Access Tracking of radio stars with the minitrack system(Editor no identificado, 1963-07) Woodman Pollitt, Ronald FranciscoThis report will discuss the possibilities of using the Minitack system with a wider predetection Bandwidth in conjunction with the Narrow Band Tracking Filter for the tracking of Radio Stars.Item Open Access Phase measurement/display subsystem for the Apollo re-entry tracking system(NASA, 1963-12-13) Woodman Pollitt, Ronald FranciscoA combined system consisting of an Interferometer and a Range System has been proposed (Reference #1) for tracking the Apollo spacecraft during the re-entry phase. The system herein discussed processes the output of the above system and performs the following functions.Item Open Access A Narrow-Band Tracking Filter(NASA, 1964-01-17) Woodman Pollitt, Ronald FranciscoThe characteristics of a servo phase-lock tracking filter is described herein. The filter tracks a 100 cps carrier with a bandwidth of either 0.3 cps or 0.03 cps. The advantages of this type filter and its use is also discussed.Item Open Access The rocket interferometer tracking (RIT) system(NASA, 1965) Spafford, Michael; Wiack, Richard; Woodman Pollitt, Ronald FranciscoA Rocket Interferometer Tracking (RIT) system is described. It uses a modified 108 Me Minitrack receiver converted for 73.6 Me operation and a newly developed phase measuring system. The output of the system is real time direction cosine data for two channels, East-West and North-South, in analog and digital form. The analog data are recorded on an x-y recorder and on a strip chart recorder; and the digital data are automatically recorded on punched tape. The RIT system has been integrated with the ranging portion of the Radio Doppler Interferometer Tracking system (RADINT) at the Wallops Island Launch facility, and records the range data on the same punched tape.Item Open Access Incoherent scattering of electromagnetic waves by a plasma(Harvard University, 1967) Woodman Pollitt, Ronald FranciscoThis thesis is concerned with the theory of incoherent scattering by a plasma, i. e., with the statistical description of the electromagnetic waves scattered by the termal electron density fluctuations in a plasma which has been illuminated by anelectromagnetic wave of certain frequency. We have treated the problema starting from first principles, tacking a new approach and removing in the process some of the limitations inherent in other approaches taken so far for the solution of this problema. We have used this approach to solve, uo to the inclusión of some numerical results, the pending problema of the effect of ion-ion “Coulomb collisions” on the ion gyro-resonances predicted by existent collision less theories; this is an important aspect of the theory in connection with the application of incoherent scattering for the study of the ionosphere.Item Restricted On the control of the F-region drift velocity by the E-region electric field: experimental evidence(Elsevier, 1969) Balsley, Ben B.; Woodman Pollitt, Ronald FranciscoExperimental evidence is presented which shows a good correlation between velocity variations of 1. (1) the vertical motions of the F-region electrons in the equatorial ionosphere, and 2. (2) the horizontal motions of electrons in the underlying E-region. This observation supports the theory that the E-region electric fields are projected into the F-region along the electrically equipotential magnetic field lines.Item Restricted Methods for the measurement of vertical ionospheric motions near the magnetic equator by incoherent scattering(American Geophysical Union, 1969-03-01) Woodman Pollitt, Ronald Francisco; Hagfors, T.Methods are discussed for the measurement of motions of the ionosphere by means of Doppler shifts of incoherent scatter frequency spectra. It is found that velocities can be measured with an accuracy of better than a few meters per second with integration times of a few minutes, provided the antenna beam us directed approximately perpendicular to the geomagnetic field.Item Open Access Statistical study of equatorial scintillations at Ancon, Peru(Instituto Geofísico del Perú, 1970) Tisnado, G.; Woodman Pollitt, Ronald Francisco; Pomalaza, J.The 136 MHz interferometric system at the past NASA Satellite Tracking Station in Ancón, Perú, consists of two orthogonal baselines aligned along the North-South and East-West directions. A sizable number of interferometric records intended far operational tracking was spoiled by large amplitude and phase fluctuations. Ir - regularities In the ionosphere, those associated with the spread-F phenomena, are the cause of these fluctuations (scintillations). In most of the distorted records the North-South baseline interferometer shows only a slight distort(on from the expected satellite graph whlle in the East-West interferometer the distortions are severe. This clearly shows the anisotropy of the irregularities and that they are elongated and aligned the magnetic field lines(Z) as have been found by other authors. The absence of North-South phase distortions when EastWest distortions are present facilitates the detection of weak scintillations against the background noise. Far the purpose of this report the East-West baseline interferometric distortion was taken as an indication of scintillations.Item Open Access Investigación ¿Para qué?(Instituto Geofísico del Perú, 1970-03-19) Woodman Pollitt, Ronald FranciscoEl avance que ha experimentado la humanidad en los últimos decenios se debe pura y exclusivamente a la investigación. Los avances científicos y tecnológicos que tanto nos impresionan se deben el mayor y mejor conocimiento que tiene el hombre en todas las diferentes ciencias y sus tecnologías afines. De dónde proceden todos estos nuevos conocimientos? Todos, exclusivamente todos, son frutos de la investigación. No existe ningún otro procedimiento para incrementar el conocimiento de la humanidad que no sea la investigación. Esto lo podríamos tomar aún como la definición misma de la investigación: investigación es toda aquella actividad del hombre destinada a incrementar los conocimientos de la humanidad.Item Open Access A progress report on scintillation observations at Ancón And Jicamarca observatories(Goddard Space Flight Center, GSFC, 1970-10) Pomalaza, José; Woodman Pollitt, Ronald Francisco; Tisnado, Gilberto; Sandoval, Jaime; Guillén, AlbertoThe purpose of this report is to present a preliminary analysis of the data collected in connection with NASA contract work with ESSA (ESSA contract No. E22-9-70(N)). Under this contract a study of equatorial ionospheric irregularities using satellite transmissions is being performed.Item Restricted Inclination of the geomagnetic field measured by an incoherent scatter technique(American Geophysical Union, 1971-01-01) Woodman Pollitt, Ronald FranciscoA technique to measure the direction of the geomagnetic field by using incoherent scatter techniques is described. The technique has been used to measure the inclination of the magnetic field at the Jicamarca Radar Observatory with an accuracy of the order of 1 minute of arc in the height range from 200 to 800 km. The corresponding inclinations obtained from the Goddard Space Flight Center (12/66) and the International Geomagnetic Reference Field (10/68) models are found to be about 1° in error.Item Open Access Jicamarca incoherent scatter observations during the march 1970 storm(World Data Center A, 1971-04) Woodman Pollitt, Ronald FranciscoThe purpose of this note is to report on ionospheric observations taken at Jicamarca (lº N Magnetic Latitude) during the March 8, 1970 magnetic storm. This report includes measurements of the electron density, electron temperature and vertical drift (or E-W electric field) for the 7, 8 and 9 of March 1970. These measurements are complemented by C-4 ionograms and magnetic field measurements taken at the Huancayo Observatory which is located at the same magnetic latitude 100 km east from the Jicamarca Observatory. We are including Huancayo AH magnetograms to illustrate our discussion. The data reported here are still under study and it is being reported in response to the request of the World Data Center A, Upper Atmosphere Geophysics, in its effort to gather world-wide data taken during the magnetic storm in a single publication. Therefore, we shall present the experimental facts limiting our discussion and conclusions to those which can be ,derived from simple inspection of the records. The techniques used to gather the data have been reported previously. The electron densities have been obtained using the Faraday rotation method and the electron temperatures using the cross correlation technique, both systems have been described by Farley [1969a,b). The technique to obtain the vertical drift (E-W electric field) is described by Woodman and Hagfors [1969). The three parameters were measured almost simultaneously. We do not have quiet day measurements of density and temperature sufficiently close to the day of the storm to be taken as a control day. The reader will have to refer to the statistical behavior of these parameters as measured at Jicamarca and reported by J. P. McClure, D. T. Farley and R.Cohen ll970J and J. P. McClure [1970). We have included here the statistical behavior of vertical drifts for the same season taken from Woodman [1970).Item Open Access Ionospheric drift velocity measurements at Jicamarca, Peru (July 1967 - March 1970)(World Data Center A, 1971-10) Balsley, Ben B.; Woodman Pollitt, Ronald FranciscoThis report is a collection of measurements of electrón drift velocity in the E and F regions of the equatorial ionosphere, made at the Jicamarca Radar Observatory (dip latitude ~1°N). The data consist of about eighty days of observations during the period July 1967 to March 1970. The measurements consist of (1) the vertical component of the electrón drift velocity in the F región, and (2) the east-west component of the electrón drift velocity in the E región. Other components of the drifts have been measured but the data are sparse and have not been included here. The horizontal component (H trace) of the magnetic field strength records of Huancayo, Perú, has also been included for reference. The purpose of this report is to make these data available to the scientific community. Comparison between these measurements and other geophysical phenomena should aid in the understanding of a variety of ionospheric and magnetospheric processes. This type of data continúes to be taken at JRO from time to time. For information regarding the more recent data, we suggest contacting either of the authors of this report. The data included in this report are also available in digital form on magnetic tape and punched cards.Item Open Access Interfase para acoplar un sistema de conversión Analógico/Digital a una computadora DATACRAFT 6024(Instituto Geofísico del Perú, Radio Observatorio de Jicamarca, 1972) Guillén C., Alberto; Woodman Pollitt, Ronald FranciscoMuchos procesos para su estudio óptimo por medio de computadoras requieren de diferentes sistemas de transducción. El presente trabajo describe el diseño de un sistema digital para acoplar un sistema de mulplex y de conversión analógica/digital a una computadora, permitiendo el procesamiento simultáneo de hasta 8 señales y con velocidades de hasta 500 mil muestras por segundo. El diseño ha aplicado al sistema de computación del Radio Observatorio de Jicamarca, uno de los observatorios del Instituto Geofísico del Perú. Este sistema permitirá el procesamiento de señales analógicas producto de diferentes proyectos de investigación científica tales como física ionosférica, sismología, infrasonido, cintilaciones, oceanografía, etc. El sistema diseñado podría adecuarse para el acoplamiento de otros sistemas de conversión analógica a otras computadoras involucradas en proyectos de investigación científica.Item Open Access Simultaneous measurements of the electric field in the auroral zone and at the equator during intense magnetic activity(Max-Plank Institute für Aeronomie, 1972) Kelley, M.C.; Gonzáles, C.; Mozer, F.S.; Woodman Pollitt, Ronald FranciscoSimultaneous balloon measurements of the auroral zone electric field in Alaska and of the vertical drift velocity of the region at Jicamarca, Peru during the great flow of August 1972 are presented.· The eastward electric field component at the equator was correlated, with a 20 minute time delay, to the westward component of the auroral zone field at College, Alaska. The equatorial horizontal component actually reversed in sign from the normal westward value and, simultaneously, the electrojet then flowing over the dayside hemisphere (at Trivandrum, India, fer example) was greatly depressed. These results show that intense auroral current systems can grossly affect both the normal dynamo current patterns at low latitudes en the dayside and the polarization fields responsible fer the worldwide low latitude zonal electric field component.Item Restricted East-west ionospheric drifts at the magnetic equator(Instituto Geofísico del Perú, 1972-01-01) Woodman Pollitt, Ronald FranciscoA technique has been developed to measure the electromagnetic east-west drift velocity of the F region ionosphere by means of the Jicamarca incoherent scatter radar. Results show a fairly consistent behavior from day to day even during a magnetically disturbed day. Velocities are westward with a maximum of the order of 50 m/sec during the day, and eastward with a maximum of the order of 135 m/sec during the night. They are shown as experimental evidence for the superrotation of the neutral atmosphere at equatorial latitudes, but with a velocity smaller than the values inferred from satellite drag.Item Restricted Synthesis of data obtained at Jicamarca, Peru, during the September 11, 1969, eclipse(American Geophysical Union, 1972-02) Sterling, D. L.; Hanson, W. B.; Woodman Pollitt, Ronald FranciscoContinuous measurements of electron temperatures, electron concentrations, and vertical plasma drift were made at Jicamarca during the September 11, 1969, solar eclipse. Control measurements were made on September 13, 1969. Synthesis of the observed electron concentrations was made, using a model that solved the time‐dependent electron‐ion continuity equations. Ions O+, NO+, O2+, and N2+ were treated. Physical and chemical processes pertinent to the F region were considered in a realistic way. At noon, 300 km above Jicamarca, we obtained the values q = 290−3 sec−1 for the O+ production rate, β = 1.94 × 10−4 sec−1 for the loss coefficient, and H = 59 km for the atomic oxygen scale height. All large‐scale features observed in the F2 region were synthesized by the model. This synthesis was not sensitive to a simultaneous 30% reduction of q and β.