The outflow of ionospheric nitrogen ions: A possible tracer for the altitude‐dependent transport and energization processes of ionospheric plasma

Though limited, the existing observational data set indicates that N+ is a significant ion in the ionosphere, and its concentration varies with season, time of day, solar cycle, latitude, and geomagnetic conditions. Knowledge of the differential transport of heavy versus light ionospheric species can provide the connection between the macroscale dynamics and microscale processes that govern the near‐Earth space. The mass distribution of accelerated ionospheric ions reflects the source region of the low‐altitude ion composition, and the minor ion component can serve as a tracer of ionospheric processes since they can have a significant influence on the local plasma dynamics.Key PointsThough limited, the existing observational data indicate N+ as a signification in the ionosphereDifferential transport of heavy versus light ionospheric speciesN+ ion could dominate the ionospheric outflow during disturbed conditionsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134456/1/jgra52903_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134456/2/jgra52903.pd

Exploring Storm Time Ring Current Formation and Response on the Energy Input.

While extensive research has been made over the last decades regarding the storm-time dynamics, there are still unanswered questions regarding the ring current formation and plasmasphere evolution, specifically about the ring current response on the energy input. Large-scale data analysis and global magnetospheric simulations provide complementary alternatives for exploring highly complex coupling of the solar wind-ionosphere-magnetosphere system. Superposed Epoch analysis of intense storms data suggests that a distinct time stamp is needed in order to resolve certain solar wind features. However, when it comes to hot proton at geosynchronous orbit, the choice of reference time primarily matters to accurately describe the size of peaks, while the presence and time evolution is unaltered by it. Examination of the role the transient spikes in the solar wind parameters play in the development of magnetic storms, reveals that changes in the energy input produce a nonlinear response of the inner magnetosphere. While initial increases in the energy input enhance the magnetospheric response, as the power transferred to the system is increased, the growth of the ring current is stalled and a saturation limits sets in. A threshold in the energy input is necessary for the ring current to develop, while the short time scale fluctuations in the solar wind parameters did not have a significant contribution. This implies the existence of an internal feedback mechanism as the magnetosphere acts as a low-pass filter of the IMF, limiting the energy flow in the magnetosphere. Further, the main characteristic in determining IMF Bz fluctuation periodicity transfer of solar wind mass and energy to the inner magnetosphere, is the peak signal to noise ratio in the power spectrum of the input parameter, suggesting that a ratio of 10 is needed in order to trigger a similar periodicity in the magnetosphere response. Theoretical and numerical modifications to an inner magnetosphere model (HEIDI) were implemented, accommodating for a non-dipolar arbitrary magnetic field. With HEIDI fully incorporated into the SWMF, an examination of model sophistication on our scientific findings can be explored. Initial simulations have been conducted and the results are discussed.Ph.D.Space and Planetary PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/77847/1/rilie_1.pd

Steady State Characteristics of the Terrestrial Geopauses

The boundary separating solar wind plasma from ionospheric plasma is typically thought to be the magnetopause. A generalization of the magnetopause concept called the geopause was developed by Moore and Delcourt (1995, https://doi.org/10.1029/95RG00872). The geopause is a surface defined where solar wind quantities equal the ionospheric quantities. Geopause studies have helped characterize magnetospheric systems. However, comparative studies between the geopauses to the magnetopause have not been conducted. In this paper, we analyze the influence of inner boundary composition and interplanetary magnetic field (IMF) orientation on the steady state terrestrial geopauses and the magnetopause. This study simulates the Earth’s magnetosphere by using the multifluid capabilities of the Block Adaptive Tree Solar wind Roe-type Upwind Scheme magnetohydrodynamics model within the Space Weather Modeling Framework. The simulations show that the dayside magnetopause was not influenced by the presence of oxygen in the outflow for both IMF orientations and was larger than the other geopauses. In contrast, the nightside magnetopause was sensitive to the conditions in the outflow. The nightside magnetopause was smaller than the other geopauses with southward IMF. With northward IMF, the nightside magnetopause was the largest structure in comparison with the plasma-based geopauses. Our results indicate that no single boundary surface dictates the transition from a solar wind dominated plasma to ionosphere dominated plasma.Key PointsFour definitions of the geopause are compared: number density, mass density, plasma pressure, and last closed field line (magnetopause)Multifluid magnetohydrodynamic modeling is used to calculate these geopauses for idealized north and south interplanetary magnetic fieldThe magnetopause is farthest out during north interplanetary field, but the plasma geopauses are farthest during south fieldPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151281/1/jgra55008_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151281/2/jgra55008.pd

Perspective Chapter: Defining and Applying the FMEA Process Method in the Field of Industrial Engineering

The analysis of failure modes and effects (FMEA) is a method of analyzing the potential failure of a product or process and developing an action plan aimed at their prevention and increased quality of products, processes, and job production environments. As a method of critical analysis, FMEA has very clear objectives: determination of the weaknesses of a technical system; initiating causes of failure-seeking components; analysis of the environmental impacts, safety of operation, the product value; provision of corrective actions to remove the causes of the occurrence of defects; provision of a plan to improve product quality and maintenance; determining the needs of technology and modernization of production; increasing the level of communication between departments of working people at hierarchical levels. FMEA should be used before taking the product. Subsequently, there is no point, only because the customer demands it, to achieve FMEA. Therefore, FMEA must be within organizational conduct. This chapter describes the FMEA method and presents studies about the improvement of the quality process for some products from industrial engineering by using FMEA, such as: axis for packaging, assembly “stator Housing,” composite parts used in the railway field. The potential causes of the defects were studied, and improvement measures were proposed

A numerical study of the correspondence between paths in a causal set and geodesics in the continuum

This paper presents the results of a computational study related to the path-geodesic correspondence in causal sets. For intervals in flat spacetimes, and in selected curved spacetimes, we present evidence that the longest maximal chains (the longest paths) in the corresponding causal set intervals statistically approach the geodesic for that interval in the appropriate continuum limit.Comment: To the celebration of the 60th birthday of Rafael D. Sorki

Distributed Agent-Based Online Auction System

This paper concerns the design and development of a distributed agent-based online system for English auctions. The proposed system is composed of two parts: an Agent-based Auction Server and a Web-based Graphical User Interface. The first part of our work brought about the advantages introduced by the multi-agent systems technology to the high-level of abstraction, modularity and performance of the server architecture and its implementation. On the server side, bids submitted by auction participants are handled by a hierarchical organization of agents that can be efficiently distributed on a computer network. This approach avoids the bottlenecks of bid processing that might occur during periods of heavy bidding, like for example snipping. We present experimental results that show a significant improvement of the server throughput compared with the architecture where a single auction manager agent is used for coordinating the participants for each active auction that is registered with the server. The second part of our work involved analysis of external functionalities, implementation and usability of a prototype online auction system that incorporates the Agent-based Auction Server. Our solution is outlined in terms of information flow management and its relation to the functionalities of the system. The main outcome of this part of the work is a clean specification of the information exchanges between the agent and non-agent software components of the system. Special attention is also given to the interoperability, understood here as successful integration of the different data communication protocols and software technologies that we employed for the implementation of the system

A review of N+ observations in the ionosphere-magnetosphere system

Most studies have yet to consider and assess the transport and energization of N+ ions throughout the ionosphere-magnetosphere system, in addition to that of O+ and other heavy ion species. The limited observational record of N+ presence in near-Earth plasma, partly due to instrument limitations to distinguish ion species of similar masses, has obscured its significant contribution to the near-Earth plasma. This letter reviews the most notable observations of N+ ions, starting from the early low altitude measurements from Sputnik III in the ionosphere to the measurements reported by the Enhanced Polar Outflow Probe (e-POP) mission. The available observational data set suggests that nitrogen ions are constant companions of outflowing oxygen ions, and their abundances vary with season, solar cycle, time of day, and geomagnetic activity. This strong record of nitrogen presence in the ionosphere-magnetosphere system raises the question of ionic composition and the need for caution when interpreting O+ measurements from current missions

Ionospheric control of the dawn‐dusk asymmetry of the Mars magnetotail current sheet

This study investigates the role of solar EUV intensity at controlling the location of the Mars magnetotail current sheet and the structure of the lobes. Four simulation results are examined from a multifluid magnetohydrodynamic model. The solar wind and interplanetary magnetic field (IMF) conditions are held constant, and the Mars crustal field sources are omitted from the simulation configuration. This isolates the influence of solar EUV. It is found that solar maximum conditions, regardless of season, result in a Venus‐like tail configuration with the current sheet shifted to the −Y (dawnside) direction. Solar minimum conditions result in a flipped tail configuration with the current sheet shifted to the +Y (duskside) direction. The lobes follow this pattern, with the current sheet shifting away from the larger lobe with the higher magnetic field magnitude. The physical process responsible for this solar EUV control of the magnetotail is the magnetization of the dayside ionosphere. During solar maximum, the ionosphere is relatively strong and the draped IMF field lines quickly slip past Mars. At solar minimum, the weaker ionosphere allows the draped IMF to move closer to the planet. These lower altitudes of the closest approach of the field line to Mars greatly hinder the day‐to‐night flow of magnetic flux. This results in a buildup of magnetic flux in the dawnside lobe as the S‐shaped topology on that side of the magnetosheath extends farther downtail. The study demonstrates that the Mars dayside ionosphere exerts significant control over the nightside induced magnetosphere of that planet.Plain Language SummaryMars, which does not have a strong magnetic field, has an induced magnetic environment from the draping of the interplanetary magnetic field from the Sun. It folds around Mars, forming two “lobes” of magnetic field behind the planet with a current sheet of electrified gas (plasma) behind it. The current sheet is not directly behind the planet but rather shifted toward the dawn or dusk direction. It is shown here that one factor controlling the location of the current sheet is the dayside ionosphere. At solar maximum, the ionosphere is dense, the magnetic field slips easily by the planet, and the current sheet is shifted toward dawn. At solar minimum, the ionosphere is relatively weak, the magnetic field slippage is slowed down, and the current sheet shifts toward dusk.Key PointsThere is a systematic Y (i.e., dawn‐dusk) asymmetry in the location of the Martian magnetotail current sheet in modified MSE coordinatesThe asymmetry is controlled by ionospheric conditions, shifting to the dawn (‐Y) during solar maximum and to the dusk during solar minimumThe shift found in this study is not a function of crustal fields, which were omitted, or solar wind conditions, which were held constantPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137681/1/jgra53609_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137681/2/jgra53609.pd

Testing the necessity of transient spikes in the storm time ring current drivers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95070/1/jgra20908.pd