Bulletin of the American Physical Society
21st Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 64, Number 8
Sunday–Friday, June 16–21, 2019; Portland, Oregon
Session E5: BIEP: Ejecta II |
Hide Abstracts |
Chair: Billy Buttler, LANL Room: Broadway I/II |
Monday, June 17, 2019 3:30PM - 4:00PM |
E5.00001: Material ejection from surface defects in laser shock-loaded metallic foils. Invited Speaker: Thibaut De Resseguier Ejecta production upon the breakout of a shock wave at a rough surface has been the subject of extensive research work for about six decades. For a few years, we have investigated how laser-driven shocks could provide original, complementary data on this issue, over specific ranges of high loading pressures, very short pulse durations (ns-order), small dimensions (tens of micrometers) and extremely high strain rates. Selected results will be shown in various metals (Cu, Sn, Al, Au), with either single triangular grooves of controlled depths and sharp angles or periodic, quasi-sinusoidal perturbations of different amplitudes and wavelengths. Experimental data will include (i) measurements of jet velocities using both optical shadowgraphy and Photonic Doppler Velocimetry, (ii) post-recovery evidence of the jetting process, (iii) attempts to evaluate ejecta size distributions using fast shadowgraphy or fragment recovery, and (iv) ultra-fast laser based x-ray radiography to estimate mass ejection. Results will be compared with the predictions of analytical models, numerical simulations, and data obtained by other teams from explosive-based experiments, over much larger temporal and spatial scales. Thus, both interest and limitations of laser shocks for this particular field of shock physics will be illustrated and discussed. [Preview Abstract] |
Monday, June 17, 2019 4:00PM - 4:15PM |
E5.00002: Development of high-power laser platforms to study metal ejecta interactions Alison Saunders, Suzanne Ali, Jon Eggert, Tomorr Haxhimali, Channing Huntington, Leo Kirsch, Brandon Morgan, Fady Najjar, Hye-Sook Park, Hans Rinderknecht Understanding the interactions of ejecta with surfaces and other ejecta has relevance to fields that seek to study spacecraft shielding, planetary impacts, and materials physics. The literature contains many examples of experiments and modeling efforts that examine the underlying physics of ejecta generation, but there are very few examples of experiments that measure the effects of ejecta interactions. In the past, these experiments have been limited to single-interaction studies on facilities such as gas guns. We choose to extend ejecta interaction studies to high-power laser facilities to take advantage of the higher repetition rates, the repeatability of drive conditions, and the advanced time-resolved diagnostics suites. We present results from initial experiments on the OMEGA and OMEGA-EP lasers and report on the development of platforms to study ejecta interactions. The experiments make use of micron-sized titanium and tin particles accelerated by high-power laser drives. [Preview Abstract] |
Monday, June 17, 2019 4:15PM - 4:30PM |
E5.00003: Development of a high resolution ps laser imaging diagnostic for microjetting characterization Arnaud Sollier, Emilien Lescoute When a shock wave emerges at a metal free surface presenting geometrical defects such as pits, scratches, or grooves, ejected matter (ejecta) can be emitted from these defects in the form of thin jets expanding ahead of the main surface and breaking up into small particles. This process is referred to as microjetting. Over the last few years, we have used laser shock loading in order to expand microjetting investigatations over ranges of small spatial scales ($\approx \mu m$), extremely high loading rates ($\approx 10^7 s^{-1}$) and very short pressure pulses ($\approx ns$). A variety of measurement techniques have been used to determine the properties of ejecta clouds. Here, we present the development of a new ps laser imaging diagnostic intended to overcome the limitations of our current transverse optical shadowgraphy setup. We describe our experimental setup and show the results of our first experiments performed using both visible (532 nm) and UV (355 nm) lightning of the sample. These results are compared to those obtained at LANL under high explosive loading using ultraviolet in-line Fraunhofer holography, and also to molecular dynamics (MD) simulations performed by our CEA colleagues at lower space and time scales. [Preview Abstract] |
Monday, June 17, 2019 4:30PM - 4:45PM |
E5.00004: Hydrodynamic studies in support of high-power laser experiments to study metal ejecta interactions Tomorr Haxhimali, Fady Najjar, Petros Tzeferacos, Alison Saunders Shock-driven material can emit a fine spray of ejecta from its free surface. Understanding the dynamic and interaction of the metal ejecta is important to areas of study as diverse as industrial safety, astrophysics, spacecraft shielding, additive manufacturing and inertial confinement fusion. In this work we present results from hydrodynamic simulation studies in support of designing experiments on the OMEGA and OMEGA-EP lasers. We use a combination of two hydrodynamic codes that capture different physical aspects of the ejecta dynamics. Fields, like pressure and velocity, of elements produced in the ablated part of material are computed using FLASH code. These are then used as input in a ``handshaking'' region to numerical predictions using finite element and/or the smoothed particle hydrodynamics formulation with ALE3D (Arbitrary Lagrangian Eulerian) code to capture shock propagation and the dynamics of the ejecta. [Preview Abstract] |
Monday, June 17, 2019 4:45PM - 5:00PM |
E5.00005: Electrically stimulated high speed microjet for medical applications Hwi-chan Ham, Jack Yoh Painless needle-free drug injection can be realized using the principle of energy focusing into an infinitesimal area with underwater spark discharge. The power supply unit charges the capacitor with the energy of ~2.2 J, thereby releasing the charged energy upon the focusing point of the water chamber. Consequently, joule heating of the water by dielectric breakdown phenomenon generates the cavitation bubbles, and the liquid drug is accelerated to the speed of sound, being ejected out from a micro sized orifice. The resulting microjet speed of 350 m/s within the response time of 10 µs is reached. This fast response time enables the micro volume of liquid jet to penetrate the skin epidermis. We build the rapid repetition cycle of spark discharging so that the device injects microliters of drug at the rate of 10~20 shots per second, thereby the injection volume is controlled. The equivalent power consumption is 60 watts. The device replaces the previously developed laser-driven injector that requires 2200 watts at a much higher cost of operation [Park, et al., “Er:YAG laser pulse for small dose splashback-free microjet transdermal drug delivery,” Optics Letters, 37(18), pp. 3894-3896, (2012)] [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700