There is great interest in applying magnetohydrodynamic (MHD) simulation techniques to the designs of electrical high explosive (HE) initiators, for the purpose of better understanding a design's sensitivities, optimizing its performance, and/or predicting its useful lifetime. Two MHD-capable LLNL codes, CALE and ALE3D, are being used to simulate the process of ohmic heating, vaporization, and plasma formation in exploding bridgewires (EBW). Initiation of the HE is simulated using Ignition & Growth reactive flow models. 1-D, 2-D and 3-D models have been constructed and studied. The models provide some intuitive explanation of the initiation process and are useful for evaluating the potential impact of identified aging mechanisms (such as the growth of intermetallic compounds or powder sintering). The end product of this work is a simulation capability for evaluating margin in proposed, modified or aged initiation system designs.

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The project management task under the project was completed and related to the development of a plan for the implementation of the project and is thus not relevant to final report. For this reason it is not included.

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If inflation occurred with a reheat temperature > T{sub PQ}, axions from the decay of global axion strings and domain walls would make an important contribution to the cosmological energy density, comparable to that from vacuum misalignment. Several groups have numerically studied the evolution of axion strings and walls in the past, however substantial uncertainties remain in their contribution to the present density {Omega}{sub a,string+wall} {approx} 1-100 (f{sub a}/10{sup 12} GeV){sup 7/6}, where f{sub a} is the axion decay constant. I will describe the numerical methods used in our simulations and show results for several string and wall configurations.

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Photograph of columns holding up the balcony above the front entrance to the Comal County courthouse in New Braunfels, Texas.

Photograph of a second floor balcony in a courtroom in Gonzales County courthouse in Gonzales, Texas.

Photograph of a second floor balcony on the exterior of the Gonzales County courthouse, above the front entrance, in Gonzales, Texas.

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Photograph of the base of two columns on the exterior of the Caldwell County courthouse in Lockhart, Texas.

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Photograph of the base of two columns on the front exterior of the Caldwell County courthouse in Lockhart, Texas.

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Photograph of a wooden bench pushed against a wall in the Caldwell County courthouse in Lockhart, Texas. A man stands in the open door to the right.

Photograph of four wooden benches on the first floor of a courtroom in the Gonzales County courthouse in Gonzales, Texas. A balcony is visible to the right.

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Photograph of several rows of wooden benches in a courtroom in the Comal County courthouse in New Braunfels, Texas.

Photograph of wooden benches in a courtroom in the Gonzales County courthouse in Gonzales, Texas.

Photograph of a bird's eye view of a courtroom in the Gonzales County courthouse in Gonzales, Texas. There are twelve jury seats to the right, and tables and chairs around the room.