arXiv subjects

Archana Kumari

Publications and source records attributed to Archana Kumari.

5 recordsLinked to original sources

arXiv2024

PIC simulations of laser-induced proton acceleration by resonant nanoantennas for fusion

Rapid recent development in laser technology and methods learned from relativistic heavy ion physics led to new possibilities for fusion. Using a Hydrogen rich UDMA-TEGDMA polymer fusion target, laser irradiation ionizes the target. If we implant nanoantennas into the target resonating to the laser light frequency massive number of electrons of the ionized plasma resonate within the nanoantenna forming a so called nanoplasmonic wave. Our kinetic model simulation with a Hydrogen target indicates that the field of these resonating electrons attracts and accelerates the surrounding protons of the plasma to multi-MeV energy. These protons are then energetic enough to achieve nuclear transmutation and fusion reactions. Without resonating nanoantenna there is no such collective proton acceleration, no energetic protons, and nuclear reactions at 30 mJ laser pulse energy.

physics.plasm-ph↗

arXiv2022

Kinetic Model Evaluation of Dynamical Properties of Nanaorod Antennas Embedded in a Polymer Carrying the Nuclei of Fusion Fuel

Recently laser induced fusion with simultaneous volume ignition, a spin-off from relativistic heavy ion collisions, was proposed, where implanted nanoantennas regulated and amplified the light absorption in the fusion target. Studies of resilience of the nanoantennas was published recently in vacuum. These studies are extended to nanoantennas embedded into a polymer, which modifies the nanoantenna's lifetime and absorption properties.

physics.plasm-ph↗

arXiv2022

SMART: a Technology Readiness Methodology in the Frame of the NIS Directive

An ever shorter technology lifecycle engendered the need for assessing new technologies w.r.t. their market readiness. Knowing the Technology readiness level (TRL) of a given target technology proved to be useful to mitigate risks such as cost overrun, product roll out delays, or early launch failures. Originally developed for space programmes by NASA, TRL became a de facto standard among technology and manufacturing companies and even among research funding agencies. However, while TRL assessments provide a systematic evaluation process resulting in meaningful metric, they are one dimensional: they only answer the question if a technology can go into production. Hence they leave an inherent gap, i.e., if a technology fulfils requirements with a certain quality. This gap becomes intolerable when this metric is applied software such as technological cybersecurity measures. With legislation such as the General Data Protection Regulation4 (GDPR) and the Network and Information Systems Directive5 (NIS-D) making reference to state of the art when requiring appropriate protection measures, software designers are faced with the question how to measure if a technology is suitable to use. We argue that there is a potential mismatch of legal aim and technological reality which not only leads to a risk of non-compliance, but also might lead to weaker protected systems than possible. In that regard, we aim to address the gaps identified with existing Technology Readiness Assessment (TRA)s and aim to overcome these by developing standardised method which is suitable for assessing software w.r.t. its market readiness and quality (in sum maturity).

cs.CY↗

arXiv2019

Magnetic glassy state at low spin state of Co3+ in EuBaCo2O5+δ (δ = 0.47) cobaltite

The magnetic glassy state is a fascinating phenomenon, which results from the kinetic arrest of the first order magnetic phase transition. Interesting properties, such as metastable magnetization and nonequilibrium magnetic phases, are naturally developed in the magnetic glassy state. Here, we report magnetic glass property in the low spin state of Co3+ in EuBaCo2O5+δ (δ = 0.47) cobaltite at low temperature (T < 60 K). The measurements of magnetization under the cooling and heating in unequal fields, magnetization relaxation and thermal cycling of magnetization show the kinetic arrest of low magnetization state below 60 K. The kinetically arrested low temperature magnetic phase is further supported through the study of isothermal magnetic entropy, which shows the significant entropy change. The present results will open a new window to search the microscopic relation between the spin state transitions and the kinetic arrest induced magnetic glassy phenomena in complex materials.

cond-mat.mtrl-sci↗

arXiv2019

Electron doping induced magnetic glassy state in phase separated YBaCo$_2$O$_{5.5-δ}$

The structural, magnetic and transport properties of the layered RBaCo$_2$O$_{5.5}$ cobaltites are sensitive to the oxygen stoichiometry. In this present study, we report the presence of a low-temperature magnetic glassy state in electron-doped polycrystalline YBaCo$_2$O$_{5.5}$ cobaltite. The ac magnetization studies show the absence of conventional spin glass features, while the various dc magnetization studies demonstrate the presence of non-equilibrium magnetic glassy state at low temperature. The magnetic glassy state of this sample results from the kinetic arrest of the first order ferro (or ferri) to antiferromagnetic transition. The role of electron doping in the occurrence of magnetic glassy phenomena is discussed in terms of magnetic phase separation involving the Co3+/Co2+ clusters of the ferrimagnetic phase in the Co3+/Co3+ antiferromagnetic matrix.

cond-mat.str-el↗