scholarly journals Separation of the geomagnetic variation field on the ground into external and internal parts using the spherical elementary current system method

2003 ◽  
Vol 55 (3) ◽  
pp. 117-129 ◽  
Author(s):  
Antti Pulkkinen ◽  
◽  
Olaf Amm ◽  
Ari Viljanen
Keyword(s):  
Current System ◽  
Geomagnetic Variation ◽  
System Method

scholarly journals Applying inversion techniques to derive source currents and geoelectric fields for geomagnetically induced current calculations

2014 ◽  
Vol 32 (10) ◽  
pp. 1263-1275 ◽  
Author(s):  
J. S. de Villiers ◽  
P. J. Cilliers
Keyword(s):  
Power Systems ◽  
Current System ◽  
Skin Depth ◽  
Domain Model ◽  
Earth Model ◽  
Model Parameters ◽  
Geomagnetic Variation ◽  
Geomagnetically Induced Currents ◽  
Ionospheric Currents ◽  
Geomagnetic Fields

Abstract. This research focuses on the inversion of geomagnetic variation field measurement to obtain source currents in the ionosphere. During a geomagnetic disturbance, the ionospheric currents create magnetic field variations that induce geoelectric fields, which drive geomagnetically induced currents (GIC) in power systems. These GIC may disturb the operation of power systems and cause damage to grounded power transformers. The geoelectric fields at any location of interest can be determined from the source currents in the ionosphere through a solution of the forward problem. Line currents running east–west along given surface position are postulated to exist at a certain height above the Earth's surface. This physical arrangement results in the fields on the ground having the magnetic north and down components, and the electric east component. Ionospheric currents are modelled by inverting Fourier integrals (over the wavenumber) of elementary geomagnetic fields using the Levenberg–Marquardt technique. The output parameters of the inversion model are the current strength, height and surface position of the ionospheric current system. A ground conductivity structure with five layers from Quebec, Canada, based on the Layered-Earth model is used to obtain the complex skin depth at a given angular frequency. This paper presents preliminary and inversion results based on these structures and simulated geomagnetic fields. The results show some interesting features in the frequency domain. Model parameters obtained through inversion are within 2% of simulated values. This technique has applications for modelling the currents of electrojets at the equator and auroral regions, as well as currents in the magnetosphere.

scholarly journals Solar cycle 22 control on daily geomagnetic variation at Terra Nova Bay (Antarctica)

1998 ◽  
Vol 41 (5-6) ◽  
Author(s):  
L. Cafarella ◽  
A. Meloni ◽  
P. Palangio
Keyword(s):  
Solar Cycle ◽  
Time Variation ◽  
Daily Variation ◽  
Current System ◽  
Geomagnetic Variation ◽  
Field Variation ◽  
Terra Nova Bay ◽  
Polar Latitude ◽  
Observatory Data ◽  
Terra Nova

Nine summer geomagnetic observatory data (1986-1995) from Terra Nova Bay Base, Antarctica (Lat.74.690S, Long. 164.120E, 80.040S magnetic latitude) are used to investigate the behaviour of the daily variation of the geomagnetic field at polar latitude. The instrumentation includes a proton precession magnetometer for total intensity |F| digital recordings; DI magnetometers for absolute measuring of the angular elements D and I and a three axis flux-gate system for acquiring H,D Z time variation data. We find that the magnetic time variation amplitude follows the solar cycle evolution and that the ratio between minimum solar median and maximum solar median is between 2-3 for intensive elements (H and Z) and 1.7 for declination(D). The solar cycle effect on geomagnetic daily variation elements amplitude in Antarctica, in comparison with previous studies, is then probably larger than expected. As a consequence, the electric current system that causes the daily magnetic field variation reveals a quite large solar cycle effect at Terra Nova Bay.

Solar quiet daily (Sq) geomagnetic variation during minimum of solar cycle 23/24

2020 ◽  
Author(s):  
Anatoly Soloviev ◽  
Artem Smirnov
Keyword(s):  
Solar Activity ◽  
Current System ◽  
Geomagnetic Variation ◽  
Solar Cycles ◽  
Middle Latitudes ◽  
Observatory Data ◽  
Summer Hemisphere ◽  
Orthogonal Components ◽  
E Region ◽  
Good Agreement

<p class="Textbody"><span lang="EN-US">The most regular of all daily geomagnetic field variations is the so-called solar quiet, or Sq, variation. It is attributed to the two current vortices flowing in the E-region of the dayside ionosphere. We present an investigation of the time-dependent parameters of Sq variation for the historical minimum of solar activity in 2008. We apply "Measure of Anomalousness" algorithm to detection of magnetically quiet days. The global maps of seasonal Sq amplitudes of the three orthogonal components are derived using 75 INTERMAGNET and 46 SuperMAG stations at low and middle latitudes. The global Sq amplitudes are compared to the previous Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model simulations and show good agreement. Significant variability was found in Sq(X) and Sq(Y) based on the solar activity and latitude, while almost no difference is observed in Sq(Z) for across all latitudes and seasons. We analyze equivalent Sq current system using observatory data from the Australian mainland and narrow European-African latitudinal segment. Sq current system also strongly depends on solar activity, as current vortices are strongest in the local summer-hemisphere and disintegrate during local winter. The dynamics of Sq variation along the solar cycles 23 and 24 is also discussed and compared to Swarm-based spherical harmonic Sq model.</span></p>

scholarly journals Perancangan Sistem Pengarsipan Surat Masuk dan Surat Keluar pada Desa Kampung Besar Menggunakan Metode Alphabetical Filing dan Chronology System

2020 ◽  
Vol 20 (2) ◽  
pp. 514
Author(s):  
Noer Azni Septiani ◽  
Deden Haitami
Keyword(s):  
System Design ◽  
Management System ◽  
Current System ◽  
Filing System ◽  
System Method ◽  
The Village ◽  
Source Of Information

The archive is one source of information that has an important function to support the process of administration and management of an agency. All activities carried out by the agency, whether in the form of proposals, correspondence or other documents will be archived. The recorded information is evidence and documentation or memory for the agency concerned. In the village of Kampung Besar Teluknaga the letter filing system that is running is still not computerized, so that in the system there are some problems in the accuracy of the data. This study aims to create a letter management system to improve the efficiency of retrieval in the context of investigative and official reference activities. The Alphabetical Filing and Chronology System method is used in system design because it is simple and easy to implement, archiving letters to large villages in the bay using a desktop program that is easy to use in the system is also easy in terms of use and maintenance. In addition to simplifying the process of archiving letters, the system also facilitates employees in the process of making reports and searching data. The proposed system is expected to improve the current system so that it can make the filing system of incoming and outgoing letters in the village of Kampung Besar Teluknaga more effective and efficient.

scholarly journals Two Current Systems in the Preliminary Phase of Sudden Commencements in the Magnetosphere

2022 ◽  
Author(s):  
Shigeru Fujita ◽  
Takashi Tanaka
Keyword(s):  
Solar Wind ◽  
Current System ◽  
Alfven Wave ◽  
Lower Latitude ◽  
Geomagnetic Variation ◽  
Peak Displacement ◽  
Outer Magnetosphere ◽  
The Cross ◽  
Current Systems ◽  
Over Time

Abstract The geomagnetic variations of the preliminary impulse (PI) of the sudden commencement (SC) are known to show a time delay of the peak displacement and longer duration time in the higher latitudes in the pre-noon and post-noon sectors of the polar region. This peculiar behavior of the PI geomagnetic variation is associated with temporal deformation of the ionospheric PI field-aligned current (FAC) distribution into a crescent shape; its lower-latitude edge extends toward the anti-sunward direction, and its higher-latitude edge almost stays on the same longitude near noon. Numerical simulations revealed that the deformation of the FAC distribution is derived from different behaviors of the two PI current systems. The first current system consists of the FAC connected to the PI FAC in the lower latitude side of the ionosphere, the cross-magnetopause current, and the magnetosheath current (type L current system). The cross-magnetopause current is the inertia current generated in the acceleration front of the solar wind due to the sudden compression of the magnetosheath. Thus, the longitudinal speed of the type L current system in the ionosphere is the solar wind speed in the magnetosheath projected into the ionosphere. In contrast, the PI current system connected to the PI FAC at higher latitude (type H current system) consists of the upward/downward FAC in the pre-noon/post-noon sector, respectively, and dawn-to-dusk field-perpendicular current (FPC) along the dayside magnetopause. The dawn-to-dusk FPC moves to the higher latitudes in the outer magnetosphere over time. The FAC of the type H current system is converted from the FPC due to convergence of the return FPC heading toward the sunward direction in the outer magnetosphere; the return FPC is the inertia current driven by the magnetospheric plasma flow associated with compression of the magnetopause behind the front region of the accelerated solar wind. The acceleration front spreads concentrically from the subsolar point. Consequently, as the return FPC is converted to the FAC of the type H current system, it does not move much in the longitudinal direction over time because the dawn-to-dusk FPC of the type H current system moves to the higher latitudes. Therefore, the high-latitude edge of the PI current distribution in the ionosphere moves only slightly. Finally, we clarified that the FPC-FAC conversion of the type L current system mainly occurs in the region where the Alfvén speed starts to increase toward the Earth. A region with a steep gradient of the Alfvén speed like the plasmapause is not always necessary for conversion from the FPC to the FAC. We also suggest the possible field-aligned structure of the standing Alfvén wave that may occur in the PI phase.

PERENCANAAN ARSITEKTUR ENTERPRISE MENGGUNAKAN EAP DENGAN ZACHMAN FRAMEWORK (Studi Kasus : CV BIENSI FESYENINDO)

2019 ◽  
Vol 2 (1) ◽  
pp. 1-16
Author(s):  
Anjas Tryana
Keyword(s):  
Enterprise Architecture ◽  
Business Processes ◽  
Current System ◽  
System Support ◽  
Architecture Model ◽  
Use Of Resources ◽  
Application Architecture ◽  
Data Architecture ◽  
Planning Methodology ◽  
Implementation Plans

With the development of technology today, it is very important for every company to plan and develop a system to support business processes in each company. Achieving the goals of an enterprise faces challenges and changes that require strategies for effective measures and efficient use of resources. One important and increasingly widely used strategy is the use and improvement of information system support for the enterprise. This plan can utilize enterprise architecture planning methodology that produces data architecture, application architecture, technology architecture, and the direction of its implementation plan for the enterprise.CV Biensi Fesyenindo is engaged in retail garment, with branches throughout Indonesia, covering the areas of Kalimantan, Sulawesai, NTB, NTT, Bali, Java and Sumatra. In their daily activities, they carry out production to distribution processes to meet market and employee needs.The enterprise architecture model used in this study is by using Enterprise Architecture Planning (EAP). EAP is a process of defining enterprise architecture that focuses on data architecture, applications and technology in supporting business and plans to implement the architecture, where the EAP method has several stages, starting from planning in planning, business modeling , Current System and Technology (Current System & Technology), Data Architecture (Data Architecture), Application Architecture (Applications Architecture), Technology Architecture (Technology Architecture), Implementation Plans (Implementation Plans).The results of this study are recommendations for information systems for Fesyenindo Biensi CV in the form of enterprise architecture planing blue print planning that is successful in defining 5 main business processes, which consist of application architecture data architecture and for technological architecture to produce technology architecture proposals divided into 5 chapters 110 pages .

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