Hydrodynamic Implosion Simulation Including Relativistic Effects on Petawatt-Class Pulse Heating

A spherically symmetric fluid code that includes the relativistic effects of hot electrons has been newly developed. In the present simulations, I attempt to implode a target shell of laser fusion using a nanosecond pulse; then, an additional heating short pulse is injected into the coronal plasma surrounding a highly compressed core. I found that the relativistic effects of hot electrons on electron transport are likely to inhibit the heat flows, and to reduce thermonuclear fusion neutrons significantly. This feature may be important for off-center fast ignition and burn of fusion targets.Comment: 14 pages, 4 figures, 2 table

Is epigenome editing non-inheritable? Implications for ethics and the regulation of human applications

科学の最新動向を基に、エピゲノム編集の倫理・規制を議論. 京都大学プレスリリース. 2023-11-03.Potential inheritable effects and ethical considerations of epigenome editing. 京都大学プレスリリース. 2023-11-03.Epigenome editing offers ethical advantages with non-inheritable gene expression control. However, concerns arise regarding potential transgenerational effects in humans. Ethical and regulatory evaluation is crucial, considering recent advancements and enhanced understanding of transgenerational epigenetics in both mammals and humans

Filamentary jets as a cosmic-ray "Zevatron"

Strong, anisotropic turbulence reflecting magnetized filaments is considered, to model the diffusive acceleration of particles by shock waves in active galactic nucleus jets. We address that at knot A of the nearby M87 jet, the shock involving the filamentary turbulence can accelerate an iron nucleus to zetta-eV (ZeV; 10^{21} eV) ranges. A smaller value of the particle diffusion coefficient is found to be essential to achieve a ZeV cosmic-ray accelerator, a "Zevatron."Comment: 5 pages, 2 color figures, emulateap

Scalings of the synchrotron cut-off and turbulent correlation of active galactic nucleus jets

We propose a new analytic scaling of the cut-off frequency of synchrotron radiation from active galactic nucleus (AGN) jets that are nonuniformly filled with many filaments. The theoretical upper limit is provided independent of magnetic intensity, spectral index, coherence and correlation length of filamentary turbulence, etc., such that \nu_c\simeq 6\times 10^{20}\delta[(r-1)/r]^{4/3}(b/10^{-4}) Hz, where \delta, r and b are the Doppler beaming factor, shock-compression ratio and energy-density ratio of the perturbed/local mean magnetic field of the filaments, respectively. Combining our results with observational data for 18 extragalactic sources, a constraint on the filament correlation length is found, in order to give the number scaling of filaments. The results suggest that, in particular, the jets of compact BL Lacs possess a large number of filaments with transverse size scale smaller than the emission-region size. The novel concept of the quantization of flowing plasma is suggested.Comment: 8 pages, 4 figures, accepted for publication in MNRA

Transitive X-ray spectrum and PeV gamma-ray cutoff in the M87 jet: Electron "Pevatron"

We propose a modified version of the X-ray spectral index and an intrinsic cutoff frequency of inverse Compton radiation from the brightest knot of the M87 jet, in conjunction with an application of the new conceptions of injection and diffusive shock acceleration (DSA) of electrons in magnetized filamentary plasma to the specified source. The drop of the X-ray flux density in a transitive frequency region is associated with the interplay of ordinary synchrotron cooling and weaker magnetic fields concomitant with the smaller scale filaments that allow the electron injection, while the radio-optical synchrotron continuum is dominantly established by the major electrons that are quasi-secularly bound to larger filaments. With reference to, particularly, the updated external Compton model, we demonstrate that in the Klein-Nishina regime fading inverse Comptonization, the injected electrons can be stochastically energized up to a Lorentz factor as high as $5\times 10^{10}$ in the temporal competition with diffuse synchrotron cooling; this value is larger than that attainable for a simple DSA scenario based on the resonant scattering diffusion of the gyrating electrons bound to a supposed magnetic field homogeneously pervading the entire knot. The upper limits of the photon frequency boosted via conceivable inverse Compton processes are predicted to be of the common order of $\sim 10^{30}$ Hz. The variability of the broadband spectrum is also discussed in comparison to the features of a blazar light curve. The present scenario of a peta-eV (PeV; $10^{15}$ eV) electron accelerator, the "Pevatron," might provide some guidance for exploring untrod hard X-ray and gamma-ray bands in forthcoming observations.Comment: 34 pages, 6 figures, matches version published in Ap

On Exact Polytropic Equilibria of Self-Gravitating Gaseous and Radiative Systems: Their Application to Molecular Cloud Condensation

We propose a novel mathematical method to construct an exact polytropic sphere in self-gravitating hydrostatic equilibrium, improving the non-linear Poisson equation. The central boundary condition for the present equation requires a ratio of gas pressure to total one at the centre, which is uniquely identified by the whole mass and molecular weight of the system. The special solution derived from the Lane-Emden equation can be reproduced. This scheme is now available for modelling the molecular cloud cores in interstellar media. The mass-radius relation of the first core is found to be consistent with the recent results of radiation hydrodynamic simulations.Comment: 5 pages, 3 figures, 1 table. Accepted for publication in MNRA

Nonlinear functional relation covering near- and far-marginal stability in ion temperature gradient driven turbulence

A novel nonlinear functional relation of turbulence potential intensity, zonal flow potential intensity, and ion thermal diffusivity that accurately reproduces nonlinear gyrokinetic simulations of toroidal ion temperature gradient (ITG) driven turbulence is proposed. Applying mathematical optimization techniques to find extremal solutions in high-dimensional parameter space, the optimal regression parameters in the functional form are determined to be valid for both near- and far-marginal regime of the ITG stability including the Dimits-shift. Then, the regression error of ∼5% is accomplished. In addition, it is clarified that the intensity ratio of the zonal flow and turbulence potential intensity is a crucial factor to determine the reproduction accuracy