scholarly journals Special issue: Present achievements and new frontiers in space plasmas

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
T. Passot ◽  
F. Califano
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Space Plasma ◽  
Space Plasmas ◽  
Special Issue ◽  
Space Plasma Physics ◽  
Technological Developments ◽  
Computational Resources ◽  
Theoretical Side

Space plasma physics, pushed by the impressive recent technological developments, is undergoing a period of intense progress. This progress is achieved first at the level of observations, including both remote and in situ measurements, but also on the theoretical side, mainly by means of large scale numerical simulations made possible by the dramatic increase of computational resources. In particular, three-dimensional mainly hybrid but also fully kinetic simulations are today feasible, and large intervals in spatial and time scales can at last be accessed by fluid simulations. Addressing fundamental problems such as, e.g. magnetic reconnection, nonlinear dynamics or turbulence development in the kinetic range, are no longer just a heart's desire today.

scholarly journals ROMA (Rank-Ordered Multifractal Analyses) of intermittency in space plasmas – a brief tutorial review

2010 ◽  
Vol 17 (5) ◽  
pp. 545-551 ◽  
Author(s):  
T. Chang ◽  
C. C. Wu ◽  
J. Podesta ◽  
M. Echim ◽  
H. Lamy ◽  
...  
Keyword(s):  
Large Scale ◽  
Auroral Zone ◽  
Space Plasmas ◽  
Dynamic Interactions ◽  
Stochastic Media ◽  
Mhd Simulations ◽  
Field Fluctuations ◽  
In Situ Observations ◽  
Magnetospheric Cusp

Abstract. Intermittent fluctuations are the consequence of the dynamic interactions of multiple coherent or pseudo-coherent structures of varied sizes in the stochastic media (Chang, 1999). We briefly review here a recently developed technique, the Rank-Ordered Multifractal Analysis (ROMA), which is both physically explicable and quantitatively accurate in deciphering the multifractal characteristics of such intermittent structures (Chang and Wu, 2008). The utility of the method is demonstrated using results obtained from large-scale 2-D MHD simulations as well as in-situ observations of magnetic field fluctuations from the interplanetary and magnetospheric cusp regions, and the broadband electric field oscillations from the auroral zone.

The MLT distribution and detailed structure of ring current:  MMS observations

2021 ◽  
Author(s):  
Xin Tan ◽  
Malcolm Dunlop ◽  
Xiangcheng Dong ◽  
Yanyan Yang ◽  
Christopher Russell
Keyword(s):  
Current Density ◽  
Large Scale ◽  
Ring Current ◽  
Current System ◽  
Radial Profile ◽  
Three Dimensional ◽  
Current Density Distribution ◽  
Magnetic Storms ◽  
In Situ Data

<p>The ring current is an important part of the large-scale magnetosphere-ionosphere current system; mainly concentrated in the equatorial plane, between 2-7 R<sub>E</sub>, and strongly ordered between ± 30 ° latitude. The morphology of ring current directly affects the geomagnetic field at low to middle latitudes. Rapid changes in ring current densities can occur during magnetic storms/sub-storms. Traditionally, the Dst index is used to characterize the intensity of magnetic storms and to reflect the variation of ring current intensity, but this index does not reflect the MLT distribution of ring current. In fact, the ring current has significant variations with MLT, depending on geomagnetic activity, due to the influence of multiple factors; such as, the partial ring current, region 1/region 2 field-aligned currents, the magnetopause current and sub-storm cycle (magnetotail current). The form of the ring current has been inferred from the three-dimensional distribution of ion differential fluxes from neutral atom imaging; however, this technique can not directly obtain the current density distribution (as can be obtained using multi-spacecraft in situ data). Previous in situ estimates of current density have used: Cluster, THEMIS and other spacecraft groups to study the distribution of the ring current for limited ranges of either radial profile, or MLT and MLAT variations. Here, we report on an extension to these studies using FGM data from MMS obtained during the period September 1, 2015 to December 31, 2016, when the MMS orbit and configuration provided good coverage. We employ the curlometer method to calculate the current density, statistically, to analysis the MLT distribution according to different geomagnetic conditions. Our results show the clear asymmetry of the ring current and its different characteristics under different geomagnetic conditions.</p>

A New Synergic-Assembly Strategy Towards Three-Dimensional (3D) Hollow Nanoarchitectures

2008 ◽  
Vol 8 (12) ◽  
pp. 6208-6222 ◽  
Author(s):  
Changzheng Wu ◽  
Yi Xie
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Building Blocks ◽  
Growth Direction ◽  
The Self ◽  
Assembly Process ◽  
Next Generation ◽  
One Pot ◽  
Assembly Strategy

Large-scale synthesis and assembly of meso-, micro- and nanostructured building blocks with the desired orientations are of great interest for the next-generation nanoarchitecture design. On the consideration that the traditional synthetic methodologies for nanostructures often produce tangled nanounits, how to align the nanounits into the ordered orientation at high production yield is a great challenge to current methods. The present review describes a facile and controllable way to grow and assemble the 3D hollow nanoarchitectures, with the utilization of the synergic effects of hollowing process from the self-produced templates and the highly anisotropic growth of nanounits of the target materials in one-pot reaction. In this process, the building block nanounits spontaneously in-situ form owing to their highly anisotropic internal structure, while the self-produced templates act as the supporter and growth-direction guidance for the in-situ formed nanounits. Therefore, the whole assembly process is simple, controllable and without the complicated manipulations. Herein, in the light of the different kinds of self-produced templates involved in the assembly process, recent developments based on the new synergic-assembly strategy are reviewed according to the classifications: (1) self-produced gas bubble template strategy; (2) self-produced homogeneous solid template strategy; (3) self-produced heterogeneous solid template strategy. Notably, the synergic-assembly methodology described in this review provides a newly essential way to construct and assemble nanoarchitectures facilely and controllably, and is also a crucial step for the next-generation of nanoarchitecture design in the near future. In conclusion, the challenges and prospects for the future are discussed.

scholarly journals Special Session 3 The Virtual Observatory in action: new science, new technology, and next generation facilities

2006 ◽  
Vol 2 (14) ◽  
pp. 577-578
Author(s):  
Nicholas A. Walton ◽  
Andrew Lawrence ◽  
Roy Williams
Keyword(s):  
Large Scale ◽  
New Technology ◽  
Virtual Observatory ◽  
New Science ◽  
Astronomical Databases ◽  
Large Databases ◽  
Very Large Databases ◽  
Technological Developments ◽  
Computational Resources ◽  
The Way

The vision of the Virtual Observatory (VO) is to make access to astronomical databases as seamless and transparent as browsing the World Wide Web is today. It will federate the data flows from current and future facilities and large scale surveys, and the computational resources and new tools necessary to fully exploit them. This requires both technological developments and an international commitment to standardisation and working culture. Increasingly, it will alter the way that astronomers do science, and the way that future facilities and projects plan for their data management, and the scientific exploitation of their data. It will make an impact on a wide variety of astronomical topics, but especially those using very large databases, and those needing a multiwavelength approach, or more generally the use of multiple archives.

scholarly journals Particle energization in space plasmas: towards a multi-point, multi-scale plasma observatory

2021 ◽  
Author(s):  
Alessandro Retinò ◽  
Yuri Khotyaintsev ◽  
Olivier Le Contel ◽  
Maria Federica Marcucci ◽  
Ferdinand Plaschke ◽  
...  
Keyword(s):  
Paradigm Shift ◽  
White Paper ◽  
Space Plasmas ◽  
Space Plasma Physics ◽  
Astrophysical Plasmas ◽  
Multi Scale ◽  
Technical Leadership ◽  
Important Field ◽  
Particle Energization

AbstractThis White Paper outlines the importance of addressing the fundamental science theme “How are charged particles energized in space plasmas” through a future ESA mission. The White Paper presents five compelling science questions related to particle energization by shocks, reconnection, waves and turbulence, jets and their combinations. Answering these questions requires resolving scale coupling, nonlinearity, and nonstationarity, which cannot be done with existing multi-point observations. In situ measurements from a multi-point, multi-scale L-class Plasma Observatory consisting of at least seven spacecraft covering fluid, ion, and electron scales are needed. The Plasma Observatory will enable a paradigm shift in our comprehension of particle energization and space plasma physics in general, with a very important impact on solar and astrophysical plasmas. It will be the next logical step following Cluster, THEMIS, and MMS for the very large and active European space plasmas community. Being one of the cornerstone missions of the future ESA Voyage 2050 science programme, it would further strengthen the European scientific and technical leadership in this important field.

Nonlinear Lorentz Model for Explicit Integration of Optical Nonlinearity in FDTD

2021 ◽  
Vol 35 (11) ◽  
pp. 1272-1273
Author(s):  
Charles Varin ◽  
Rhys Emms ◽  
Graeme Bart ◽  
Thomas Fennel ◽  
Thomas Brabec
Keyword(s):  
Large Scale ◽  
Dispersion Model ◽  
Three Dimensional ◽  
Optical Nonlinearity ◽  
Limiting Factor ◽  
Explicit Integration ◽  
Time Step ◽  
Numerical Convergence ◽  
Optical Effects ◽  
Computational Resources

Including optical nonlinearity in FDTD software in a stable, efficient, and rigorous way can be challenging. Traditional methods address this challenge by solving an implicit form of Maxwell’s equations iteratively. Reaching numerical convergence over the entire numerical space at each time step demands significant computational resources, which can be a limiting factor for the modeling of large-scale three-dimensional nonlinear optics problems (complex photonics devices, laser filamentation, ...). Recently, we proposed an explicit methodology based on a nonlinear generalization of the Lorentz dispersion model and developed example cases where it was used to account for both linear and nonlinear optical effects. An overview of this work is proposed here.

Three-dimensional seismic characterisation of large-scale sandstone intrusions in the lower Palaeogene of the North Sea: completely injected vs. in situ remobilised sandbodies

2010 ◽  
Vol 22 (4) ◽  
pp. 517-532 ◽  
Author(s):  
Ewa Szarawarska ◽  
Mads Huuse ◽  
Andrew Hurst ◽  
Wytze De Boer ◽  
Liwei Lu ◽  
...  
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Three Dimensional ◽  
The North ◽  
The North Sea

scholarly journals On the violation of the zeroth law of turbulence in space plasmas

2021 ◽  
Vol 87 (3) ◽  
Author(s):  
R. Meyrand ◽  
J. Squire ◽  
A.A. Schekochihin ◽  
W. Dorland
Keyword(s):  
Energy Input ◽  
Large Scale ◽  
Magnetic Energy ◽  
Plasma Turbulence ◽  
Space Plasmas ◽  
Transition Range ◽  
Kinetic Transition ◽  
Strong Resemblance ◽  
Common Situation

The zeroth law of turbulence states that, for fixed energy input into large-scale motions, the statistical steady state of a turbulent system is independent of microphysical dissipation properties. This behaviour, which is fundamental to nearly all fluid-like systems from industrial processes to galaxies, occurs because nonlinear processes generate smaller and smaller scales in the flow, until the dissipation – no matter how small – can thermalise the energy input. Using direct numerical simulations and theoretical arguments, we show that in strongly magnetised plasma turbulence such as that recently observed by the Parker Solar Probe spacecraft, the zeroth law is routinely violated. Namely, when such turbulence is ‘imbalanced’ – when the large-scale energy input is dominated by Alfvénic perturbations propagating in one direction (the most common situation in space plasmas) – nonlinear conservation laws imply the existence of a ‘barrier’ at scales near the ion gyroradius. This causes energy to build up over time at large scales. The resulting magnetic-energy spectra bear a strong resemblance to those observed in situ, exhibiting a sharp, steep kinetic transition range above and around the ion-Larmor scale, with flattening at yet smaller scales. The effect thus offers a possible solution to the decade-long puzzle of the position and variability of ion-kinetic spectral breaks in plasma turbulence. The existence of the ‘barrier’ also suggests that, how a plasma is forced at large scales (the imbalance) may have a crucial influence on thermodynamic properties such as the ion-to-electron heating ratio.

scholarly journals A dynamic analysis of in-situ stress state at the Upper Tamakoshi Hydroelectric Project area, Nepal

2018 ◽  
Vol 23 ◽  
pp. 42-47
Author(s):  
Krishna Kanta Panthi ◽  
Chhatra Bahadur Basnet
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Large Scale ◽  
Three Dimensional ◽  
In Situ Stress ◽  
Energy And Environment ◽  
Hydroelectric Project ◽  
Detailed Assessment ◽  
Local Shear

 The in-situ stress condition in the rock mass is influenced by both tectonic and geological environment, such as faulting and shearing in the rock mass. This influence is of considerable magnitude in the Himalayan region where the tectonic movement is active, resulting periodic dynamic earthquakes. Each large-scale earthquake causes both accumulation and sudden release of strain energy instigating changes in the in-situ stress environment in the rock mass. This paper evaluates the influence of local shear fault on the in-situ stress state along the shot crete lined high pressure tunnel of Upper Tamakoshi Hydroelectric Project, 456 MW in Nepal. A detailed assessment of the in-situ stress state is carried out by using both; measured data and three-dimensional numerical analysis using FLAC3D. The analysis includes evaluation on the possible changes in the in-situ stress state in the rock mass caused by seismic activities (dynamic loading). HYDRO Nepal JournalJournal of Water, Energy and Environment Issue: 23Year: 2018

The Future of Transplant Biology and Surgery

2018 ◽  
Author(s):  
Marc Colaco ◽  
Anthony Atala
Keyword(s):  
Regenerative Medicine ◽  
Large Scale ◽  
Three Dimensional ◽  
Organic Substrates ◽  
Experimental Phase ◽  
Three Dimensional Printing ◽  
The Future ◽  
Technological Developments ◽  
Synthetic Scaffolds ◽  
Dimensional Printing

Although allograft organs remain the gold standard for transplantation, the availability of donor organs has forced us to search for alternatives. Regenerative medicine and tissue engineering offer a solution for this issue. Through the use of synthetic scaffolds and organic substrates, we have been able to generate neoorgans for a variety of different body systems. Although these neoorgans remain largely in the experimental phase, the results are promising, and recent technological developments have made production a realistic endeavor on the large scale. In this review, we highlight recent advances in the field of regenerative medicine and their application to the future of transplant surgery.  This review contains 6 figures, 2 tables and 42 references Key Words: bioengineering, biomaterial, bioreactor, decellularized organs, organ scaffolds, regenerative medicine, stem cell, three-dimensional printing

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