Intensity/time profiles of solar particle events at one astronomical unit

A description of the intensity-time profiles of solar proton events observed at the orbit of the earth is presented. The discussion, which includes descriptive figures, presents a general overview of the subject without the detailed mathematical description of the physical processes which usually accompany most reviews

Overview of STIP intervals 15-19

Five STIP Intervals for special scientific study of solar and interplanetary phenomena were designated between February 1984 and March 1986. The first two intervals were selected retrospectively after unusual periods of solar activity; the remaining three intervals were selected in advance in conjunction with anticipated spacecraft configurations and measurements. In this overview the historical background of these STIP Intervals and a summary of the rationale in the selection of these particular time periods for concentrated studies are presented

An update on the correlation between the cosmic radiation intensity and the geomagnetic AA index

A statistical study between the cosmic ray intensity, as observed by a neutron monitor, and of the geomagnetic aa index, as representative of perturbations in the plasma and interplanetary magnetic field in the heliosphere, has been updated to specifically exclude time periods around the reversal of the solar magnetic field. The results of this study show a strong negative correlation for the period 1960 through 1968 with a correlation coefficient of approximately -0.86. However, there is essentially no correlation between the cosmic ray intensity and the aa index for the period 1972-1979 (i.e. correlation coefficient less than 0.16). These results would appear to support the theory of preferential particle propagation into the heliosphere vis the ecliptic during the period 1960-1968 and via the solar polar regions during 1972-1979

Visual detection of point source targets

Visual detection of point source targets in simulated star field backgroun

Tracking excited states in wave function optimization using density matrices and variational principles

We present a method for finding individual excited states' energy stationary points in complete active space self-consistent field theory that is compatible with standard optimization methods and highly effective at overcoming difficulties due to root flipping and near-degeneracies. Inspired by both the maximum overlap method and recent progress in excited state variational principles, our approach combines these ideas in order to track individual excited states throughout the orbital optimization process. In a series of tests involving root flipping, near-degeneracies, charge transfers, and double excitations, we show that this approach is more effective for state-specific optimization than either the naive selection of roots based on energy ordering or a more direct generalization of the maximum overlap method. Furthermore, we provide evidence that this state-specific approach improves the performance of complete active space perturbation theory. With a simple implementation, a low cost, and compatibility with large active space methods, the approach is designed to be useful in a wide range of excited state investigations.Comment: 13 pages, submitted to JCT

The use of the McIlwain L-parameter to estimate cosmic ray vertical cutoff rigidities for different epochs of the geomagnetic field

Secular changes in the geomagnetic field between 1955 and 1980 have been large enough to produce significant differences in both the verical cutoff rigidities and in the L-value for a specified position. A useful relationship employing the McIlwain L-parameter to estimate vertical cutoff rigidities has been derived for the twenty-five year period

Long term measurement network for FIFE

The objectives were: to obtain selected instruments which were not standard equipment on the Portable Automated Mesometeorological (PAM) and Data Control Platform (DCP) stations; to assist in incorporation of these instruments onto the PAM and DCP stations; to help provide routine maintenance of the instruments; to conduct periodic instrument calibrations; and to repair or replace malfunctioning instruments when possible. All of the objectives were or will be met soon. All instruments and the necessary instrument stands were purchased or made and were available for inclusion on the PAM and DCP stations before the beginning of the IFC-1. Due to problems beyond control, the DCP stations experienced considerable difficulty in becoming operational. To fill some of the gaps caused by the DCP problems, Campbell CR21-X data loggers were installed and the data collected on cassette tapes. Periodic checks of all instruments were made, to maintain data quality, to make necessary adjustments in certain instruments, to replace malfunctioning instruments, and to provide instrument calibration. All instruments will be calibrated before the beginning of the 1988 growing season as soon as the weather permits access to all stations and provides conditions that are not too harsh to work in for extended periods of time

Calibration of field reference panel and radiometers used in FIFE 1989

Remote sensing of the earth's surface features involves the measurement of reflected solar radiation and the interpretation of the data in biophysical terms. Reflected radiation is a function of the surface properties and incident solar irradiance. The amount of radiation reflected from a surface is compared to the amount of solar radiation received at the surface as a means of comparing information from different times of day as well as for different days of the year. Thus, it is imperative to calibrate the instruments used to measure the incoming and reflected radiation