Energetics of a long-implosion-time, 12-cm-diameter argon-gas-puff Z pinch at 6.5 MA

R.J. Commisso, J.P. Apruzese, D. Mosher, D.P. Murphy, B.V. Weber, J.W. Banister, B.H. Failor, J.S. Levine, N. Qi, H.M. Sze, A. Bixler, P.L. Coleman (+8 others)
2007 2007 16th IEEE International Pulsed Power Conference  
We carry out an energy-inventory analysis for a 12-cmdiameter, argon gas-puff shot on the Saturn generator. From the measured pinch inductance time history, we infer the average radius of the pinch current, r ind , and the total work done on the pinch, E coupled , both as functions of time. The kinetic energy as a function of time, E KE , is inferred from r ind and the measured initial mass distribution, assuming all of the mass is accreted as in a snowplow. The results show that early in the
more » ... that early in the implosion, E coupled ≈ E KE . However, when the pinch begins to radiate significantly, E KE begins to decrease while E coupled continues to increase. The increase in coupled energy goes into plasma internal energy, E int , i.e., ionization and thermal energies of the z-pinch plasma, and total radiation, E rad . During the time of K-shell emission, the significant (~ 150-kJ) increase in E coupled is reflected in approximately the same increase in E rad . There is agreement between E int at the time of peak K-shell emission inferred from E coupled and measurements of E rad , and E int inferred from independent spectroscopic measurements combined with an atomic-physics model. ABSTRACT We carry out an energy-inventory analysis for a 12-cmdiameter, argon gas-puff shot on the Saturn generator. From the measured pinch inductance time history, we infer the average radius of the pinch current, rind, and the total work done on the pinch, Ecoupled, both as functions of time. The kinetic energy as a function of time, EKE, is inferred from rind and the measured initial mass distribution, assuming all of the mass is accreted as in a snowplow. The results show that early in the implosion, Ecoupled ¡Ö EKE. However, when the pinch begins to radiate significantly, EKE begins to decrease while Ecoupled continues to increase. The increase in coupled energy goes into plasma internal energy, Eint, i.e., ionization and thermal energies of the z-pinch plasma, and total radiation, Erad. During the time of K-shell emission, the significant (~ 150-kJ) increase in Ecoupled is reflected in approximately the same increase in Erad. There is agreement between Eint at the time of peak K-shell emission inferred from Ecoupled and measurements of Erad, and Eint inferred from independent spectroscopic measurements combined with an atomic-physics model. 15 . SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 7 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
doi:10.1109/ppps.2007.4652535 fatcat:yudwce5dbvgo7pqtrne5ovpw4a