Plasmoids in Reconnecting Current Sheets: Solar and Terrestrial Contexts Compared

Magnetic reconnection plays a crucial role in violent energy conversion occurring in the environments of high electrical conductivity, such as the solar atmosphere, magnetosphere, and fusion devices. We focus on the morphological features of the process in two different environments, the solar atmosphere and the geomagnetic tail. In addition to indirect evidence that indicates reconnection in progress or having just taken place, such as auroral manifestations in the magnetosphere and the flare loop system in the solar atmosphere, more direct evidence of reconnection in the solar and terrestrial environments is being collected. Such evidence includes the reconnection inflow near the reconnecting current sheet, and the outflow along the sheet characterized by a sequence of plasmoids. Both turbulent and unsteady Petschek-type reconnection processes could account for the observations. We also discuss other relevant observational consequences of both mechanisms in these two settings. While on face value, these are two completely different physical environments, there emerge many commonalities, for example, an Alfven speed of the same order of magnitude, a key parameter determining the reconnection rate. This comparative study is meant as a contribution to current efforts aimed at isolating similarities in processes occurring in very different contexts in the heliosphere, and even in the universe.Comment: 21 pages, 9 figures, in press at J. Geophys. Res. (Space Physics), for the special NESSC section on Comparative Aspects of Magnetic Reconnectio

U.S. AND PRC STRATEGIC COMPETITION: CYBER AND RISK AVERSION

The People’s Republic of China (PRC) altered its calculations from the aftermath of the 1990 Persian Gulf war and placed emphasis on the importance of technology and information. The PRC created the Strategic Support Force (SSF), which became operational in 2015, and includes space, cyber, and electronic warfare capabilities under one command. Meanwhile, the U.S. has wrapped itself in structural and cultural limitations, which hinder operational tempo. This thesis examined how the Department of Defense can adjust its positions on Cyber Titles, authorities, permissions, and risk aversion in leadership to maintain a competitive edge against the threat of the PRC’s SSF in the cyber domain. This thesis used system dynamics to model the economies of both the U.S. and the PRC into cyber capabilities, which resulted in an understanding that allocating additional money alone will not solve the core issue. Understanding the limitations of cultural biases, and using decision-making tools such as prospect theory, leaders can make more effective decisions. Through proper education of staff officers about cyber capabilities and their effects, integration of cyber operations at combat training centers, and pushing permissions and rules of engagements down to Task Force Commanders, the U.S. can overcome the structural and cultural obstacles.Major, United States ArmyMajor, United States Marine CorpsApproved for public release. Distribution is unlimited

‘Yes-in-my-backyard’: Spatial differences in the valuation of forest services and local co-benefits for carbon markets in México

Forests provide many and large benefits, including cost-efficient climate change mitigation. However international carbon markets have not stimulated the demand for forestry offsets. Domestic market-mechanisms are emerging inmany countries and forests could be highly valued through these policies asmost of the benefits produced by forests are enjoyed locally. Here, a choice experiment explores drivers of valuation and willingness to pay for forest carbon services in voluntary markets in Mexico by comparing the valuation of citizens from four regions to test geographical preference for projects (n = 645). Findings from multinomial-logit models show valuation of forest carbon services is transferable and citizens would pay more for offsets from projects closer to their homes. Proximate forests provide a range of co-benefits to local users, including environmental services and opportunities for recreation. Factors related to valuation include sense of responsibility, previous knowledge of carbon emissions, previous visits to the sites, regional identification and the valuation of local environmental services (e.g. improvements in local air quality). Knowledge of spatial heterogeneity in valuation of the use of forest services can help to design market-based instruments by identifying highly valued areas for environmental services programs and carbon markets

A STUDY ON REGIONAL CIRCULAR ECONOMY SYSTEM AND ITS CONSTRUCTION, OPERATION AND SUGGESTION FOR SHANGHAI

The characteristics of the traditional linear economic model are high consumption, high emission and low efficiency. Economic development is still largely at the expense of the environment and requires a natural resource investment. This can realize rapid economic development but resource depletion and environmental pollution become increasingly serious. In the 1990\u27s a new economic model, circular economics, began to enter our vision. The circular economy maximizes production and minimizes the impact of economic activities on the ecological environment through organizing the activities through the closed-loop feedback cycle of resources - production - renewable resource . Circular economy is a better way to solve the contradictions between the economic development and resource shortages. Developing circular economy has become the major strategic initiatives to achieving sustainable development in countries all over the world. The evaluation of the development of circular economics is a necessary step for regional circular economy development. Having a quantitative evaluation of circular economy can better monitor and reveal the contradictions and problems in the process of the development of recycling economy. This thesis will: 1) Create an evaluation model framework and new types of industries and 2) Make an evaluation of the Shanghai circular economy currently to analyze the situation of Shanghai in the development of circular economy. I will then propose suggestions about the structure and development of Shanghai circular economy

Decoupling User Interface Design Using Libraries of Reusable Components

The integration of electronic and mechanical hardware, software and interaction design presents a challenging design space for researchers developing physical user interfaces and interactive artifacts. Currently in the academic research community, physical user interfaces and interactive artifacts are predominantly designed and prototyped either as one-off instances from the ground up, or using functionally rich hardware toolkits and prototyping systems. During this prototyping phase, undertaking an integral design of the interface or interactive artifact’s electronic hardware is frequently constraining due to the tight couplings between the different design realms and the typical need for iterations as the design matures. Several current toolkit designs have consequently embraced component-sharing and component-swapping modular designs with a view to extending flexibility and improving researcher freedom by disentangling and softening the cause-effect couplings. Encouraged by early successes of these toolkits, this research work strives to further enhance these freedoms by pursuing an alternative style and dimension of hardware modularity. Another motivation is our goal to facilitate the design and development of certain classes of interfaces and interactive artifacts for which current electronic design approaches are argued to be restrictively constraining (e.g., relating to scale and complexity). Unfortunately, this goal of a new platform architecture is met with conceptual and technical challenges on the embedded system networking front. In response, this research investigates and extends a growing field of multi-module distributed embedded systems. We identify and characterize a sub-class of these systems, calling them embedded aggregates. We then outline and develop a framework for realizing the embedded aggregate class of systems. Toward this end, this thesis examines several architectures, topologies and communication protocols, making the case for and substantial steps toward the development of a suite of networking protocols and control algorithms to support embedded aggregates. We define a set of protocols, mechanisms and communication packets that collectively form the underlying framework for the aggregates. Following the aggregates design, we develop blades and tiles to support user interface researchers

Magnetohydrodynamic Simulations Of Plasma Dynamics In The Magnetospheric Cusp Region

Thesis (Ph.D.) University of Alaska Fairbanks, 2012The Earth's magnetospheric cusp regions are rich in interesting plasma physics. The geomagnetic cusps offer solar wind plasma a relatively easy entry point into the magnetosphere through magnetic reconnection with the interplanetary magnetic field. The cusp regions are characterized by various interesting and important observations such as low energy particle precipitation, significant outflow of ionospheric material, and the frequent presence of energetic particles in regions of depressed magnetic field strength. The physical mechanisms that lead to these observations is often unresolved, for instance the acceleration mechanism for energetic cusp populations is not understood, nor is it known what implications they may have on magnetospheric dynamics. It is however, well accepted that magnetic reconnection plays a critical role in the vicinity of the cusps and is likely responsible for much of the dynamics in the region. Modeling of the geomagnetic cusps is notoriously challenging. Global magnetospheric models have proven indispensable in the study of the interaction of the solar wind plasma with the Earth's magnetosphere, however, the exterior cusp region poses a significant challenge for these models due to their relatively small scale. I have developed a mesoscale cusp-like magnetic field model in order to provide a better resolution (up to 300 km) of the entire cusp region than is possible in these global models. Typical observational features of the high-altitude cusps are well reproduced by the simulation. Results for both strongly northward and strongly southward interplanetary magnetic field indicate extended regions of depressed magnetic field and strongly enhanced plasma beta (cusp diamagnetic cavities). The Alfvenic nature of the outer boundary between the cusp and magnetosheath, in addition to the flow characteristics in the region, indicate that magnetic reconnection plays an important role in structuring the high-altitude cusp region. The inner boundaries with magnetosphere are gradual transitions forming a clear funnel. These cavities further present a unique configuration in which reconnecting magnetic flux tubes may gain a significant amount of flux tube entropy (H = p1/gammaV) through topological changes due to magnetic reconnection

Black hole and brane production in TeV gravity: A review

In models with large extra dimensions particle collisions with center-of-mass energy larger than the fundamental gravitational scale can generate non-perturbative gravitational objects such as black holes and branes. The formation and the subsequent decay of these super-Planckian objects would be detectable in particle colliders and high energy cosmic ray detectors, and have interesting implications in cosmology and astrophysics. In this paper we present a review of black hole and brane production in TeV-scale gravity.Comment: 40 pages, 14 figures, submitted to the Int. Jou. Mod. Phys.