Proton Radiography and Fast Electron Propogation Through Cyliderically Compressed Targets

R. Jafer,L. Volpe,D. Batani,M. Koenig,S. Baton,E. Brambrink,F. Perez,K. Lancaster,M. Galimberti,R. Heathcote,M. Tolley,Ch. Spindloe,P. Koester,L. Labate,L. Gizzi,C. Benedetti,A. Sgattoni,M. Richetta,J 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.21

The paper describes the key points contained in the short term HiPER (High Power laser Energy Research) experimental road map, as well as the results of two phases of the experiment performed in “HiPER dedicated time slots. Experimental and theoretical results of relativistic electron transport in cylindrically compressed matter are presented. This experiment was achieved at the VULCAN laser facility (UK) by using four long pulse beams (∽4 × 50 J, 1 ns, at 0.53 µm) to compress a hollow plastic cylinder filled with plastic foam of three different densities (0.1, 0.3, and 1 g cm−3). In the first phase of the experiment, protons accelerated by a picosecond laser pulse were used to radiograph a cylinder filled with 0.1 g/cc foam. Point projection proton backlighting was used to measure the degree of compression as well as the stagnation time. Results were compared to those from hard X-ray radiography. Finally, Monte Carlo simulations of proton propagation in cold and compressed targets allowed a detailed comparison with 2D numerical hydro simulations. 2D simulations predict a density of 2-5 g cm−3 and a plasma temperature up to 100 eV at maximum compression. In the second phase of the experiment, a short pulse (10 ps, 160 J) beam generated fast electrons that propagated through the compressed matter by irradiating a nickel foil at an intensity of 5 × 1018 Wcm−2. X-ray spectrometer and imagers were implemented in order to estimate the compressed plasma conditions and to infer the hot electron characteristics. Results are discussed and compared with simulations.

MODIS 적외 자료를 이용한 한반도 지역의 안정도 지수 산출

박성희,손병주,정의석,M. Koenig 한국기상학회 2005 한국기상학회 학술대회 논문집 Vol.2005 No.-

Rates of cavity filling by liquids

Seo, Dongjin,Schrader, Alex M.,Chen, Szu-Ying,Kaufman, Yair,Cristiani, Thomas R.,Page, Steven H.,Koenig, Peter H.,Gizaw, Yonas,Lee, Dong Woog,Israelachvili, Jacob N. National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.32

<P>Understanding the fundamental wetting behavior of liquids on surfaces with pores or cavities provides insights into the wetting phenomena associated with rough or patterned surfaces, such as skin and fabrics, as well as the development of everyday products such as ointments and paints, and industrial applications such as enhanced oil recovery and pitting during chemical mechanical polishing. We have studied, both experimentally and theoretically, the dynamics of the transitions from the unfilled/partially filled (Cassie-Baxter) wetting state to the fully filled (Wenzel) wetting state on intrinsically hydrophilic surfaces (intrinsic water contact angle <90 degrees, where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie-Baxter state can also exist) to determine the variables that control the rates of such transitions. We prepared silicon wafers with cylindrical cavities of different geometries and immersed them in bulk water. With bright-field and confocal fluorescence microscopy, we observed the details of, and the rates associated with, water penetration into the cavities from the bulk. We find that unconnected, reentrant cavities (i.e., cavities that open up below the surface) have the slowest cavity-filling rates, while connected or non-reentrant cavities undergo very rapid transitions. Using these unconnected, reentrant cavities, we identified the variables that affect cavity-filling rates: (i) the intrinsic contact angle, (ii) the concentration of dissolved air in the bulk water phase (i.e., aeration), (iii) the liquid volatility that determines the rate of capillary condensation inside the cavities, and (iv) the presence of surfactants.</P>

Contact Angle and Adhesion Dynamics and Hysteresis on Molecularly Smooth Chemically Homogeneous Surfaces

Chen, Szu-Ying,Kaufman, Yair,Schrader, Alex M.,Seo, Dongjin,Lee, Dong Woog,Page, Steven H.,Koenig, Peter H.,Isaacs, Sandra,Gizaw, Yonas,Israelachvili, Jacob N. American Chemical Society 2017 Langmuir Vol.33 No.38

<P>Measuring truly equilibrium adhesion energies or contact angles to obtain the thermodynamic values is experimentally difficult because it requires loading/unloading or advancing/receding boundaries to be measured at rates that can be slower than 1 nm/s. We have measured advancing-receding contact angles and loading-unloading adhesion energies for various systems and geometries involving molecularly smooth and chemically homogeneous surfaces moving at different but steady velocities in both directions, ±<I>V</I>, focusing on the thermodynamic limit of ±<I>V</I> → 0. We have used the Bell Theory (1978) to derive expressions for the dynamic (velocity-dependent) adhesion energies and contact angles suitable for both (i) dynamic adhesion measurements using the classic Johnson-Kendall-Roberts (JKR, 1971) theory of “contact mechanics” and (ii) dynamic contact angle hysteresis measurements of both rolling droplets and syringe-controlled (sessile) droplets on various surfaces. We present our results for systems that exhibited both steady and varying velocities from <I>V</I> ≈ 10 mm/s to 1 nm/s, where in all cases but one, the advancing (<I>V</I> > 0) and receding (<I>V</I> < 0) adhesion energies and/or contact angles converged toward the same theoretical (thermodynamic) values as <I>V</I> → 0. Our equations for the dynamic contact angles are similar to the classic equations of Blake & Haynes (1969) and fitted the experimental adhesion data equally well over the range of velocities studied, although with somewhat different fitting parameters for the characteristic molecular <I>length/dimension</I> or <I>area</I> and characteristic bond formation/rupture <I>lifetime</I> or <I>velocity</I>. Our theoretical and experimental methods and results unify previous kinetic theories of adhesion and contact angle hysteresis and offer new experimental methods for testing kinetic models in the thermodynamic, <I>quasi-static</I>, limit. Our analyses are limited to kinetic effects only, and we conclude that hydrodynamic, i.e., viscous, and inertial effects do not play a role at the interfacial velocities of our experiments, i.e., <I>V</I> < (1-10) mm/s (for water and hexadecane, but for viscous polymers it may be different), consistent with previously reported studies.</P> [FIG OMISSION]</BR>

Young Stellar Objects in the Massive Star-forming Regions W51 and W43

Saral, G.,Hora, J. L.,Audard, M.,Koenig, X. P.,Martí,nez-Galarza, J. R.,Motte, F.,Nguyen-Luong, Q.,Saygac, A. T.,Smith, H. A. American Astronomical Society 2017 The Astrophysical journal Vol.839 No.2

<P>We present the results of our investigation of the star-forming complexes W51 and W43, two of the brightest in the first Galactic quadrant. In order to determine the young stellar object (YSO) populations in W51 and W43 we used color-magnitude relations based on Spitzer mid-infrared and 2MASS/UKIDSS near-infrared data. We identified 302 Class I YSOs and 1178 Class II/transition disk candidates in W51, and 917 Class I YSOs and 5187 Class II/transition disk candidates in W43. We also identified tens of groups of YSOs in both regions using the Minimal Spanning Tree (MST) method. We found similar cluster densities in both regions, even though Spitzer was not able to probe the densest part of W43. By using the Class II/I ratios, we traced the relative ages within the regions and, based on the morphology of the clusters, we argue that several sites of star formation are independent of one another in terms of their ages and physical conditions. We used spectral energy distribution-fitting to identify the massive YSO (MYSO) candidates since they play a vital role in the star formation process, and then examined them to see if they are related to any massive star formation tracers such as UCH II regions, masers, or dense fragments. We identified 17 MYSO candidates in W51, and 14 in W43, respectively, and found that groups of YSOs hosting MYSO candidates are positionally associated with H II regions in W51, though we do not see any MYSO candidates associated with previously identified massive dense fragments in W43.</P>

Intercalibration of the Meteosat-7 Water Vapor Channel with SSM/T-2

Sohn, B. J.,Schmetz, J.,Tjemkes, S.,Koenig, M.,Lutz, H.,Arriaga, A.,Chung, E. S. 대한원격탐사학회 1999 International Symposium on Remote Sensing Vol.15 No.1

Proton Radiography for Inertial Confinement Fusion

L. Volpe,D. Batani,S. Baton,F. Perez,M. Koenig,Ph. Nicolai,B. Vauzour,J. J. Santos 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.51

Generation of high intensity and well collimated multi energetic proton beams from laser-matter interaction extend the possibility to use protons as a diagnostic to image imploding target in Inertial Confinement Fusion experiments in the framework of experimental road map of Hiper project (the European High Power laser Energy Research facility Project). Due to the very large mass densities reached during implosion processes, protons travelling through the target undergo a very large number of collisions which deviate protons from their original trajectory reducing Proton Radiography resolution below our expectations. Here We present a simple analytical model to study the Proton Radiography performance as a function of the main experimental parameters such as proton beam energy and target areal density. This approach leads to define two different criteria for PR resolution (called "strong" and "weak" condition) describing different experimental conditions.Finally numerical simulations using both Hydrodynamic and Monte Carlo codes are presented to validate analytical predictions.

MODIS 적외 자료를 이용한 한반도 지역의 대기 안정도 지수 산출

박성희 ( Sung Hee Park ),손병주 ( B. J. Sohn ),정의석 ( Eui Seok Chung ),M. Koenig 大韓遠隔探査學會 2006 大韓遠隔探査學會誌 Vol.22 No.6

Terra 위성에 탑재된 MODIS 적외채널의 밝기온도 자료를 이용하여 한반도 지역에 대해 안정도 지수를 산출하는 알고리즘을 개발하였다. 안정도 지수는 정역학 평형 상태하에서 연직 변위에 대한 대기의 안정도로 정의되며, 대류성 폭풍우의 가능성을 나타내는 지수로 사용된다. RDAPS의 온도와 습도 연직분포자료를 비선형 물리적 방법에 필요한 초기 추정 자료로 사용하여, KI, KO, LI, MB 지수를 산출하였고, RTTOV-7을 이용하여 물리적 복원 방법에 요구되는 긴 계산 시간을 단축하였다. 복사전달 모의를 통한 추정된 밝기온도는 관측값과 잘 일치하는 것으로 나타났다. 단기 예보에 대한 유용성을 살펴보기 위해 안정도 지수 산출 알고리즘을 급격히 발달하는 대류성 폭풍우 사례에 적용하였다. RDAPS로부터 계산된 안정도 지수 NASA에서 산출한 안정도 지수에 비해 대류운의 발달이 예상되는 지역을 보다 정확하게 예측하는 것으로 나타났다. 따라서 본 연구에서 개발된 알고리즘을 사용하여 순간 예보와 단기 예보를 향상시킬 수 있을 것으로 판단된다. An algorithm was developed to estimate stability indices (SI) over the Korean peninsula using Terra Moderate Resolution Imaging Spectroradiometer (MODIS) infrared brightness temperatures (TBs). The SI is defined as the stability of the atmosphere in the hydrostatic equilibrium with respect to the vertical displacements and is used as an index for the potential severe storm development. Using atmosphere temperature and moisture profiles from Regional Data Assimilation and Prediction System (RDAPS) as initial guess data for a nonlinear physical relaxation method, K index (KI), KO index (KO), lifted index (LI), and maximum buoyancy (MB) were estimated. A fast radiative transfer model, RTTOV-7, is utilized for reducing the computational burden related to the physical relaxation method. The estimated TBs from the radiative transfer simulation are in good agreement with observed MODIS TBs. To test usefulness for the short-term forecast of severe storms, the algorithm is applied to the rapidly developed convective storms. Compared with the SIs from the RDAPS forecasts and NASA products, the MODIS SI obtained in this research predicts the instability better over the pre-convection areas. Thus, it is expected that the nowcasting and short-term forecast can be improved by utilizing the algorithms developed in this study.

Numerical modeling of laser-driven experiments aiming to demonstrate magnetic field amplification via turbulent dynamo

Tzeferacos, P.,Rigby, A.,Bott, A.,Bell, A. R.,Bingham, R.,Casner, A.,Cattaneo, F.,Churazov, E. M.,Emig, J.,Flocke, N.,Fiuza, F.,Forest, C. B.,Foster, J.,Graziani, C.,Katz, J.,Koenig, M.,Li, C.-K.,Mein American Institute of Physics 2017 Physics of plasmas Vol.24 No.4