Bulletin of the American Physical Society
18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT)
Volume 58, Number 7
Sunday–Friday, July 7–12, 2013; Seattle, Washington
Session W7: CM.1 Equation of State: Metals |
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Chair: Scott Crockett, Los Alamos National Laboratory Room: Grand Crescent |
Thursday, July 11, 2013 4:00PM - 4:15PM |
W7.00001: Measurement of the Principal Quasi-Isentrope of Lead to $\sim$3Mbar using the ``Z'' Machine Stephen Rothman, Jean-Paul Davis, Marcus Knudson, Tom Ao, Stephen Gooding We have measured the principal quasi-isentrope of pure lead to $\sim$3 Mbar, using magnetically-driven ramp compression on SNL's ``Z'' machine. Multiple point-VISARs were used to measure the surface velocities of the compressed samples, and iterative Lagrangian analysis was used to find the wave speed as a function of ramp velocity to an accuracy of $<$2\%. This was then integrated to longitudinal stress as a function of volume on the quasi-isentrope. The experiment used a stripline configuration with samples arranged in pairs at each of 4 vertical positions on opposite drive panels: three of the four pair positions held two lead samples of different thicknesses, while the fourth consisted of one lead sample and a bare panel for drive measurement. The thicker samples of the 3 pairs experienced weak shocks at low stress so their quasi-isentrope data is unreliable there. The single-sample data was good at low stress but affected at high stress by either effects of closure of the stripline gap and / or reflections of the compression pulse from the drive-panel rear surfaces. Data from both methods overlapped at intermediate stresses so have been combined to give the required quasi-isentrope data. [Preview Abstract] |
Thursday, July 11, 2013 4:15PM - 4:30PM |
W7.00002: Tantalum on Warm Quasi-Isentropes Jeffrey Nguyen, Jonathan Belof, Daniel Orlikowski, Neil Holmes We recently carried out a series of light-gas gun experiments to study the equation of state of tantalum along warm quasi-isentropes at up to pressures above 4 Mbars. The experiments were carried out with the use of Graded Density Impactors, which allow us to access phase space regions not previously accessible. The results are consistent with calculations. We present here equation of state data of tantalum up to 5 megabars on an elevated quasi-isentrope. The data are taken on isentropes initiating from shock Hugoniot, and thus taken a significantly different path than that of the principal isentropes. Graded density impactors were used to as pressure drivers in two-stage light gas-gun experiments. The results are consistent with calculations for the elevated isentropes. [Preview Abstract] |
Thursday, July 11, 2013 4:30PM - 4:45PM |
W7.00003: Shock-Ramp Loading of Tin and Aluminum Christopher Seagle, Jean Paul Davis, Matthew Martin, Heath Hanshaw Equation of state properties for materials off the principle Hugoniot and isentrope are currently poorly constrained. The ability to directly probe regions of phase space between the Hugoniot and isentrope under dynamic loading will greatly improve our ability to constrain equation of state properties under a variety of conditions and study otherwise inaccessible phase transitions. We have developed a technique at Sandia's Z accelerator to send a steady shock wave through a material under test, and subsequently ramp compress from the Hugoniot state. The shock-ramp experimental platform results in a unique loading path and enables probing of equation of state properties in regions of phase space otherwise difficult to access in dynamic experiments. A two-point minimization technique has been developed for the analysis of shock-ramp velocity data. The technique correctly accounts for the ``initial'' Hugoniot density of the material under test before the ramp wave arrives. Elevated quasi-isentropes have been measured for solid aluminum up to 1.4 Mbar and liquid tin up to 1.1 Mbar using the shock ramp technique. These experiments and the analysis of the resulting velocity profiles will be discussed. [Preview Abstract] |
Thursday, July 11, 2013 4:45PM - 5:00PM |
W7.00004: ABSTRACT WITHDRAWN |
Thursday, July 11, 2013 5:00PM - 5:15PM |
W7.00005: Semiempirical multi-phase Equation of state of Al Gongmu Zhang, Haifeng Liu, Yanhong Zhao Equation of state(EOS) is the fundamental characteristic of matter determining its thermodynamic properties over a wide range of the phase diagram. EOS are based on a three-term Helmholtz free energy, given as a function of the specific volume V and temperature T. Semiempirical EOS use with great efficiency results obtained by theories and experimental data. Al serves as a standard material for high pressure region, the EOS for this metal need to be especially exact and reliable. We construct the EOS for Al can describe the phase solid, liquid and gas, it agrees with IEX and DAC experiment data and the other theories data well. [Preview Abstract] |
Thursday, July 11, 2013 5:15PM - 5:30PM |
W7.00006: Hugoniot-measurement experiment of high-temperature sample on W and Au for discussion of Gr\"{u}neisen parameter Tsutomu Mashimo, Keiichi Oka, Hideaki Takashima, Yuya Gomoto, Akira Yoshiasa Pressure calibration in static compression research has been undertaken on the basis of the equation of state (EOS) derived from the Hugoniot-compression curve of pressure scale materials such as Au and Pt. However, room-temperature isothermal compression curve and high-temperature compression curves have been derived by using the assumed Gr\"{u}neisen parameter, which cause lager errors in the EOS analysis. If the Hugoniot data of high-temperature sample are measured, the Gr\"{u}neisen parameter can be directly discussed, and the high temperature EOS can be accurately obtained. We have measured the Hugoniot data of room-temperature sample on Cu, W, etc. by using the high-time resolution streak camera system equipped with a powder gun and two-stage light gas gun. In this study, the Hugoniot-measurement technique of high-temperature sample using a high frequency heating apparatus was established equipped with a powder gun. The mirror-finished sample and driver plate were set on ceramic mount, and were surrounded by a high frequency heating coil. We succeeded in measurement of the Hugoniot data of high-temperature sample at 800${^\circ}$ on W, Au, etc. The detailed results and discussion of Gr\"{u}neisen parameter will be presented at the conference. [Preview Abstract] |
Thursday, July 11, 2013 5:30PM - 5:45PM |
W7.00007: Strength effect on the Hugoniot-compression curves of some metals (Cu, W and Au) Keiichi Oka, Tsutomu Mashimo, Yuya Gomoto, Hideyuki Takashima, Xun Liu, Kunihito Nagayama, Eugene Zaretsky To derive true EOS of matter from the Hugoniot data or to discuss the Gr\"uneisen parameter, we need the precise Hugoniot data, and must access the strength under shock compression to draw the hydrostatic compression curve. For this, we have refined the measurement facility and analysis procedure. The measurement accuracy of Hugoniot data had increased by constructing the high-time resolution streak photographic system consisting of rotating-mirror type streak camera and pulsed dye laser, and considering the effects of impact inclination. The Hugoniot data of copper (Cu) and tungsten (W) were measured in the pressure range up to \textgreater 200 GPa by the symmetric-impact experiment using a one-stage powder gun and two-stage light gas gun. It was found that the zero-intercept values ($C_{0})$ of $U_{S}$-$U_{P}$ relation (\textit{Us}$=C_{0}+$\textit{SUp}) of Cu and W were larger than the bulk sound velocities (3.867 and 4.023 km) by 0.14 and 0.13 km/s, respectively, which showed the effect of shear strength in plastic region. The hydrostatic-compression curves were drawn using the strength values reported by Chhabildas et al., and the equation of state (EOS) parameters were discussed. The result on gold (Au) will be also presented at the conference. [Preview Abstract] |
Thursday, July 11, 2013 5:45PM - 6:00PM |
W7.00008: Shock compression experiment for gold at an extreme pressure of 0.36Gbar driven by radiation on the Shenguang-III prototype laser facility Z. Hu, D. Yang, S. Li, X. Jiang, Y. Liu, R. Yi, T. Song, L. Guo, C. Zhang, H. Zhang, Z. Li, S. Jiang, S. Liu, J. Yang, Y. Ding, X. Li, Y. Li, K. Lan, W. Zheng In this paper, we report a radiation-driven shock compression experiment for gold at an extreme pressure around 0.36Gbar. In order to obtain such high pressure with relatively low laser energy, two main proposals were used in the target design: a smaller-size cavity to obtain higher temperature radiation resource, and impedance-match technique for pressure enhancement. The present experiment was carried out on the Shenguang-III prototype laser facility which is located at the research center of laser fusion, Mianyang, China. Eight laser beams (a total energy of 6.4kJ of 0.35$\mu $m light in 1nsec) were injected into a cavity and heat its inner wall, and then the generated x-ray radiation was used to ablate an aluminum substrate and generate shock waves. For using the impedance-match, the gold stepped sample was placed on the aluminum substrate. The shock wave velocity of 49.6 km/s was measured by a streaked optical pyrometer, and then the shock-induced pressure of 0.36Gbar was deduced using Hugoniot data of gold. [Preview Abstract] |
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