Lifeboat Foundation

The dynamics of electrons submitted to voltage pulses in a thin semiconductor layer is investigated using a kinetic approach based on the solution of the electron Boltzmann equation using particle-in-cell/Monte Carlo collision simulations. The results showed that due to the fairly high plasma density, oscillations emerge from a highly nonlinear interaction between the space-charge field and the electrons. The voltage pulse excites electron waves with dynamics and phase-space trajectories that depend on the doping level. High-amplitude oscillations take place during the relaxation phase and are subsequently damped over time-scales in the range 100 – 400 fs and decrease with the doping level. The power spectra of these oscillations show a high-energy band and a low-energy peak that were attributed to bounded plasma resonances and to a sheath effect. The high-energy THz domain reduces to sharp and well-defined peaks for the high doping case. The radiative power that would be emitted by the thin semiconductor layer strongly depends on the competition between damping and radiative decay in the electron dynamics. Simulations showed that higher doping level favor enhanced magnitude and much slower damping for the high-frequency current, which would strongly enhance the emitted level of THz radiation.

Laser interaction with foam targets is of interest for applications in the inertial confinement fusion studies and for the creation of secondary sources of energetic particles and radiation. Numerical modeling of such an interaction presents difficulties related to the sub-wavelength dimension of solid elements and high density contrast. Here, we present an analysis of laser interaction with thin wires based on the Mie theory, which demonstrates an enhanced laser absorption due to plasma resonance, and confirm this conclusion with detailed kinetic simulations. Numerical simulations also provide the characteristic time of the solid element transformation in a plasma and the energy partition between electrons and ions.

The threat actors associated with the Gootkit malware have made “notable changes” to their toolset, adding new components and obfuscations to their infection chains.

Google-owned Mandiant is monitoring the activity cluster under the moniker UNC2565, noting that the usage of the malware is “exclusive to this group.”

Gootkit, also called Gootloader, is spread through compromised websites that victims are tricked into visiting when searching for business-related documents like agreements and contracts via a technique called search engine optimization (SEO) poisoning.

AI technology generates original proteins from scratch.

I have said 3D printed houses could help with the housing crisis.

“Project Milestone serves as the world’s first 3D printed concrete “commercial housing project,” according to its maker.”

But not according to ICON 3D, and the link below shows Africa’s largest 3D printing housing project in Kenya. I have been talking about 3D printed houses for years. Its good people have caught up.

Continue reading “A couple just moved into a 3D printed concrete home for about $1,400 a month— see what it’s like to live in” »

Since the focus on Martian exploration ramped up in the mid-1990s, most of the familiarity with the Entry, Descent, and Landing (EDL) sequence of landers and rovers to the surface of other planets has taken place against the backdrop of Mars.

But when NASA‘s upcoming Dragonfly mission arrives at Titan for its own EDL, it will experience a starkly different set of conditions that both add new complexity and ease some structural considerations for the system that will deliver the rotorcraft into Titan’s atmosphere.

Circa 2013 face_with_colon_three

A ten-dimensional theory of gravity makes the same predictions as standard quantum physics in fewer dimensions.

Year 2017 face_with_colon_three

A basic question [1] in the study of the gauge-gravity duality is this: which field theories have a gravity dual? In the case of applications to actual strongly coupled systems such as the Quark–Gluon Plasma [2], [3], [4], [5], [6], this question becomes: does every realistic strongly coupled system have such a dual? To settle this, one needs to examine the most extreme cases. The most extreme strongly-coupled systems currently accessible to experiment are probably (see below) the plasmas produced by collisions of heavy ions at the LHC [7], [8] ; so one needs to consider whether holography works in this case.

In [9] we adduced evidence suggesting that it does not. The problem is a very fundamental one: it appears that the purported gravity dual in some cases does not exist when one attempts to interpret it (as one ultimately must [10]) as a string-theoretic system.

Continue reading “On the existence of a holographic description of the LHC quark–gluon plasmas” »

Year 2022, this basically could shield the earth or Mars from solar radiation if we needed it. 😗

First experimental measurement of pure electron outflows associated with magnetic reconnection driven by electron dynamics in laser-produced plasmas.

Magnetic reconnections in laser-produced plasmas have been investigated in order to better understand the microscopic electron dynamics, which are relevant to space and astrophysical phenomena. Osaka University scientists, in collaboration with researchers at the National Institute for Fusion Science and other universities, have reported the direct measurements of pure electron outflows relevant to magnetic reconnection using a high-power laser, Gekko XII, at the Institute of Laser Engineering, Osaka University in Japan. Their findings will be published today (June 30, 2022) in Springer Nature, Scientific Reports.

Continue reading “High-Power Laser Creates a Miniature Magnetosphere” »