134 research outputs found
Converging Shock-induced Blow-off Acceleration (CSBA): Towards laser acceleration of protons at nearly the speed of light
No full textThe recent advancements in both laser and target fabrication techniques have led to the enhancement of the accelerated proton cutoff energies close to 100 MeV. However, the energy spectra show a wide spread, which reduces the effective beam current to be utilized. In order to widen the possibility for high energy proton acceleration, here, we consider a different approach using micron-scale spherical hydrogen clusters, alternative to that using solid thin film targets.
Recently, we have presented a new scheme using prominent characteristics of cluster targets for achieving to the level of 300 MeV quasimonoenergetic proton bunch acceleration with a low angular divergence by utilizing the internal degree of freedom (d.o.f.). In this scheme, the collisionless shock dynamics inside the micron-scale cluster subsequently coupled with relativistically induced transparency (RIT) effect of high-intensity laser plays an important role. The external d.o.f. associated with the cluster expansion due to the sheath field is also incorporated. These multiple processes can be synchronized in a self-consistent manner once suitable conditions for the laser and the cluster are satisfied, leading to the quasimonoenergetic proton bunch acceleration. We named this process Converging Shock-induced Blow-off Acceleration (CSBA).
The result of a proof-of-principle experiment for the quasimonoenergetic proton bunch acceleration via interaction of micron-scale hydrogen cluster targets with PW-class laser pulses, conducted using the J-KAREN-P laser facility at KPSI-QST, will be presented.Workshop on Laboratory Astrophysics: Novel Development in Nonlinear Plasma Physics with Lasersconference objec
A challenge towards generation of sub-GeV quasimonoenergetic protons via the Converging Shock-induced Blow-off Acceleration (CSBA) with 10 PW laser pulses
No full textThe recent advancements in both laser and target fabrication techniques have led to the enhancement of the accelerated proton cutoff energies close to 100 MeV. In order to widen the possibility for high energy proton acceleration, we consider a different approach using micron-scale spherical hydrogen clusters, alternative to that using solid thin film targets.
Here, we introduce a new acceleration scheme, what we call CSBA (Converging Shock-induced Blow-off Acceleration), using prominent characteristics of micron-scale hydrogen cluster targets for achieving sub-GeV (0.3 GeV) quasimonoenergetic (QME) proton bunch acceleration, while maintaining a narrow energy spread (∼10%) and a small half-divergence angle (∼5°) by utilizing the internal degree of freedom (d.o.f.) of the cluster. In this scheme, the collisionless shock dynamics inside the micron-scale cluster subsequently coupled with relativistically induced transparency (RIT) effect of high-intensity laser plays an important role. The external d.o.f. associated with the cluster expansion due to the sheath field is also incorporated. These multiple processes can be synchronized in a self-consistent manner once conditions for the laser and cluster are satisfied, leading to the QME proton bunch acceleration.
By using the PW-class J-KAREN-P laser facility at KPSI-QST and the micron-scale hydrogen cluster targets, the proof-of-principle experiment for the QME proton acceleration has been successfully conducted, although the maximum proton energy is much less than that of the ideal case. In order to access the sub-GeV (0.3 GeV) QME proton acceleration, the laser peak intensity well above 1.0 × 10^22 W/cm^2 with the spot size as large as possible and the high enough laser pulse contrast is required, which could be achievable only with the ELI-NP 10 PW laser facility.
The details of the CSBA, the results of the proof-of-principle experiment at KPSI-QST, and the future outlook will be presented.1st ELI-NP User Workshopconference objec
KEKERASAN ANAK DALAM DRAMA MOTHER KARYA YUUJI SAKAMOTO: KAJIAN SOSIOLOGI SASTRA 社会学的文学研究で坂本雄二が制作されたドラマ『Mother』における児童虐待
No full textABSTRACT
Putri, Galuh Kusuma Kencana, 2018. “Child abuse in Mother drama, Writen by Yuuji Sakamoto, Study of Sociology ”, Thesis, Japanese Language and Culture, Faculty of Humanities, Diponegoro University, Semarang. Consultant: Fajria Noviana, S.S., M.Hum.
The purpose of this research is to explain the phenomenon of child abuse and goverment effort in dealing with the phenomenon in Mother drama.
The method of this research is qualitative library method. The teory used to analyse is the theory of child abuse with structural approach. Structuralism is used to analyse intrinsic elements included in drama, that are character, role and characterization; conflict; background of space and time. Meanwhile, the theory of child abuse is used to analyze the child abuse forms in this drama.
The result of this research, it can be explain that the author uses instrinsic elements to indicate the factors causing the occurance of social problems, in this case is the the violence of parents to children. Stress and problem in society can change a person’s character.
Keyword: Mother drama, child abuse, and of Socio
X ray diagnostics of hot dense plasma created by the action of 10 PW ultra-intense laser pulses on micron-scale cluster targets
No full textCombined with X-ray spectral plasma diagnostics, studies on the interaction of intense laser pulses with cluster targets provide essential information for the basic properties of matter under extreme conditions. The X-ray radiation spectra of high-temperature plasmas are formed primarily due to atomic processes occurring in it, like electron–ion collisions and the radiative or autoionization decay of ion levels. Therefore, X-ray diagnostics are employed primarily for evaluating the electron density and the temperature of the transient nonequilibrium plasmas, as well as the nonlinear processes occurring in the relativistic laser plasmas. One practical outcome is the capability to estimate the effect of laser prepulses: Without the accurate knowledge of the temporal structure of a laser pulse, theoretical calculations based on atomic and kinetic models can give a rough estimation of the cluster evolution under the influence of the laser prepulses and the main pulse by comparing the profiles of the resonance spectral lines and the hollow ion spectra.
Here we propose to introduce the focusing spectrometer with spatial resolution (FSSR) equipped with spherically bent crystals and the micron-scale cluster target, both of which have been successfully applied simultaneously in several HEDP experiments with high-intensity lasers at QST-KPSI and CEA Saclay. The introduction of these two devices promises to give absolutely unique research environment if combined with the ELI-NP 10 PW laser facility: We will start with Argon clusters to know how well the laser system performs at laser intensity of around 10^18 W/cm^2. With the increase of intensity for 1-2 orders of magnitude (around 10^20 W/cm^2), there will be a lot of H-like Argons, never observed before. With the higher laser contrasts, the spectral lines of hollow ions could be clearly identified. An observation of hollow ion spectra suggests the existence of a dense core at the moment of arrival of the main pulse, i.e. the laser contrast is extremely high enough. For the unexplored laser intensities over 10^22 W/cm^2, we try to look on Krypton K-shell spectra from Krypton clusters to examine the higher temperature and density plasmas, and try to find a way to define laser intensity from X ray spectroscopy.1st ELI-NP User Workshopconference objec
Dynamics of the boundary layer created by the explosion of a dense object in an ambient dilute gas triggered by a high power laser
No full text
Sintering Behavior of Flying Slag Particles in Entrained Bed Coal Gasifiers. 2nd Report. Production of Amorphous Slag in Laboratory.
No full textDynamics of the boundary layer created by the explosion of a dense object in an ambient dilute gas triggered by a high power laser
No full textThe dynamics of the boundary layer in between two distinct collisionless plasmas created by the interaction between a dense object modeling a cluster and a short laser pulse in the presence of an ambient gas is studied with two dimensional relativistic particle-in-cell simulations, which are found to be described by three successive processes. In the first phase, a collisionless electrostatic shock wave, launched near the cluster expansion front, reflects the ambient gas ions at a contact surface as a moving wall, which allows a particle acceleration with a narrower energy spread. In the second phase, the contact surface disappears and the compressed surface of the ambient gas ions passes over the shock potential, forming an overlapping region between the cluster expansion front and the compressed surface of the ambient gas. Here, another type of nonlinear wave is found to be evolved, leading to a relaxation of the shock structure, while continuing to reflect the ambient gas ions. The nonlinear wave exhibits a bipolar electric field structure that is sustained for a long timescale coupled with slowly evolving ion dynamics, suggesting that a quasistationary kinetic equilibrium dominated by electron vortices in the phase space is established. In the third phase, a rarefaction wave is triggered and evolves at the compressed surface of ambient gas. This is because some of the ambient gas ions tend to pass over the potential of the bipolar electric field. Simultaneously, a staircase structure, i.e., a kind of internal shock, is formed in the cluster due to the deceleration of cluster ions. Such structure formations and successive dynamics accompanied by the transitions from the shock wave phase through the overlapping phase to the rarefaction wave phase are considered to be a unique nature at the boundary layer created by an explosion of a dense plasma object in an ambient dilute plasma.journal articl
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