1. NAME AND TITLE

STORM: Solar Flare Radiation Hazard to Earth Orbiting Vehicles.

AUXILIARY ROUTINES

OSO ORBIT: Trajectory Calculation.

SOLAR FLARE: Radiation Environment Code.

DOSE: Dose Rate Calculator.

This package is retained by RSIC to preserve space technology developed in the 1960's.

2. CONTRIBUTORS

NASA, Langley Research Center, Hampton, Virginia.

Aerospace Systems and Services, Republic Aviation Corporation, Farmingdale, Long Island, New York.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 7090 and 7094.

4. NATURE OF PROBLEM SOLVED

The primary radiation incident on earth-orbiting vehicles during a solar flare is calculated. The effects of the earth's geomagnetic field have been taken into account, as well as those of a perturbing field due to the geomagnetic storm associated with a solar flare. Simple earth shadow effects have also been considered.

5. METHOD OF SOLUTION

The solar flare radiation hazard is assumed to be due to increased solar cosmic radiation and the geomagnetic storm associated with a flare. The effect of the former is obvious. The latter is caused by a change in the earth's magnetic field, resulting in a change in the natural magnetic shielding that permits more particles of greater or lesser energy to arrive than during the "quiet" magnetic state. It is further assumed that the distribution of particles a large distance from the earth's field is isotropic, and an application of Liouville's Theorem indicates that the intensity of particles in any allowed direction is the same as at their starting point. It therefore suffices to determine the allowed directions at the point in question. In the absence of magnetic effects other than that due to the earth's dipole, it is assumed that these directions are given by the classical Stormer theory, neglecting earth's shadow effect. In the presence of a magnetic disturbance the allowed Stormer cone is modified. In calculating this modification it is assumed that the cylindrical symmetry of the problem is not broken, thus enabling the modified Stormer integral of motion to be solved.

6. RESTRICTIONS OR LIMITATIONS

No information on restrictions or limitations is available at this time.

7. TYPICAL RUNNING TIME

No studies have been made to determine typical running time. Estimated running times for the sample problem on the IBM 7090 in hours: OSO ORBIT, .02; SOLAR FLARE, .04; and DOSE, .02

8. COMPUTER HARDWARE REQUIREMENTS

The codes were designed for the IBM 7094 and are compatible with the IBM 7090. A maximum of 5 tape units are required.

9. COMPUTER SOFTWARE REQUIREMENTS

The FORTRAN IV IBJOB Monitor System with standard systems, input, and output tapes is required. In addition, the following tapes are required:

1. OSO ORBIT, one pool tape which is written to be used as input to SOLAR FLARE,

2. SOLAR FLARE, tape in 1) above and another pool tape which is written to be used as input to DOSE, and

3. DOSE, tape in 2) above.

10. REFERENCES

E. Kuhn, W. T. Payne, and F. E. Schwamb, "Solar Flare Hazard to Earth-Orbiting Vehicles," RAC 1395-1 (July 1964).

E. Kuhn, W. T. Payne, and D. A. Levine, "Solar Flare Hazard to Earth-Orbiting Vehicles," RAC 1395-2 (January 1965).

"Solar Flare Hazard to Earth Orbiting Vehicles," FHR-1395-3 (April 1966).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source codes and input and output for a sample problem.

12. DATE OF ABSTRACT

January 1968; updated July 1981, February 1985.

KEYWORDS: SPACE RADIATION