MODELING

THEORETICAL COMPUTER CODES FOR ANALYSIS OF NUCLEAR DUST/DEBRIS CLOUDS CURRENTLY OVER-ESTIMATE THE DEGREE OF INTERACTION BETWEEN THE CRATER EJECTA AND THE FIREBALL BY FACTOR OF THREE OR MORE FOR NEAR-SURFACE BURSTS. MOST OF THE COLD EJECTA REMAINS CLOSE TO THE SURFACE IN A COHERENT SHEET AND DOES NOT INTERACT WITH THE HOT FIREBALL GASES. AS A RESULT, THE INITIAL COOLING OF THE FIREBALL BY THE COLD EJECTA PREDICTED BY THE CODES MAY NOT OCCUR, POSSIBLE RESULTING IN SIGNIFICANT ERRORS IN THE RATE OF RISE OF THE DUST/DEBRIS CLOUD. THE FORM OF AN ALGORITHM FOR DETERMINING THE EJECTA-FIREBALL INTERACTION FRACTION FOR A CRATERING BURST WILL BE DEVELOPED BY ANALYSIS OF EXPERIMENTAL CRATER DATA AND CALCULATED EJECTA DISTRIBUTIONS. THE ALGORITHM WILL BE IN A FORM WITH UNSPECIFIED COEFFICIENTS THAT CAN BE DETERMINED (DURING PHASE II) FROM PAST AND FUTURE EXPERIMENTAL MEASUREMENTS AND THEORETICAL CALCULATIONS FOR ARBITRARY COMBINATIONS OF YIELD, EXPLO SIVE TYPE, CHARGE GEOMETRY, HEIGHT/DEPTH OF BURST, AND GEOLOGIC MEDIUM. THE ALGORITHM WILL BE CAPABLE OF INDEPENDENT APPLICATION FOR USE WITH EXISTING DATA OR CODE RESULTS, AND ALSO AS A POST PROCESSOR FOR USE WITH NEW THEORETICAL CODE CALCULATIONS.