Longitudinal dependence of eastward and westward magnetic variations at mid-latitudes

The magnetic local time (MLT) dependence of magnetic variations on the ground at mid-latitudes caused by field-aligned currents is estimated for two cases where the distribution of the field-aligned currents is defined at the magnetosphere and at the polar ionosphere. The results show that the MLT distribution of the magnetic variations shifts eastward or westward by a few hours in the latter case because the terrestrial magnetic field declines from the geographic meridian. Whether the distribution shifts eastward or westward depends on the longitude of the observatory. This fact suggests that whether the distribution of a phenomenon propagating along the terrestrial magnetic field is mainly determined in the magnetosphere or in the ionosphere may be determined by comparing the MLT distribution of the phenomenon\u27s magnetic effect at observatories located at various longitudes

Characteristics of solar flare effect in the high-latitude ionosphere as observed by the SuperDARN radars

Sudden perturbations of the ground magnetic fields at solar flares are called geomagnetic Solar Flare Effect (SFE). An SFE is the extra ionization produced by the X-ray emission from a solar flare. We analyzed 10 intense SFE events from 1996 to 1998 using SuperDARN HF radar network and other instruments located in the northern hemisphere. Two typical ionospheric signatures associated with the solar flares are revealed, one is a sudden fade-out of backscatter echoes, and the other is an appearance or variation of field-aligned irregularities. Sudden fade-out is observed only in the sunlit hemisphere, and the appearance or variation of irregularities are observed only near the terminator. In addition, we investigated one event out of ten in detail and found that there exists a discontinuity of the electric field or conductivity around the irregularity. This fact suggests that the variation of conductivity or electric field in the E region could affect the irregularity formation in the F region

Origin of the SuperDARN broad Doppler spectra:simultaneous observation with Oersted satellite magnetometer

We perform a case study of a favorable conjunction of an overpass of the Oersted satellite with the field-of-view of the SuperDARN Syowa East radar during an interval of the southward IMF <i>B<sub>z</sub></i>. At the time, the radar observed an L-shell aligned boundary in the spectral width around the dayside ionosphere. Simultaneously, high-frequency (0.2–5Hz) magnetic field fluctuations were observed by the Oersted satellite's high-time resolution magnetometer. These magnetic field fluctuations are considered to be Alfvén waves possibly associated with the particle which precipitates into the dayside high-latitude ionosphere when magnetic reconnection occurs. It has been theoretically predicted that the time-varying electric field is the dominant physical process to expand the broad HF radar Doppler spectra. Our observation clearly demonstrates that the boundary between narrow and broad spectral widths is corresponding well to the boundary in the level of the fluctuations, which supports the previous theoretical prediction. A close relationship between electric and magnetic field fluctuations and particle precipitations during southward IMF conditions has been confirmed by many authors. The present observation allows us to suggest that the boundary between narrow and broad Doppler spectral widths observed in the dayside ionosphere is connected with the signature of the open/closed field line boundary, such as the cusp particle precipitations via electric and magnetic field fluctuations for the case of the negative IMF <i>B<sub>z</sub></i> conditions.<br><br> <b>Key words.</b> Ionosphere (ionosphere-magnetosphere interactions; plasma convection). Magnetospheric physics (magnetopause, cusp, and boundary layers

An Earth and Space Science Rubric and ePortfolio for Research Data Management

第5回京都大学研究データマネジメントワークショップ日時 : 2021年3月30日(火) 10:00-12:45 場所 : Zoomによるオンライン会議室 主催 : 京都大学学際融合教育研究推進センター葛ユニット 共催 : 京都大学学際融合教育研究推進センター、京都大学学術情報メディアセンター5th Kyoto University Research Data Management WorkshopThis presentation will describe the creation of a set of rubrics to help new researchers in Earth and Space Science learn how to make their research data available to others by publishing it in a proprietary or open science repository. While the CDL rubric for Sharing Your Data focuses on assisting researchers in deciding the extent to which they will share their data, the Earth and Space Science rubrics assist new researchers in preparing for and completing the sharing process. Four rubrics have been drafted for research data management (RDM) in Earth and Space Science: Planning for Data, Organizing Data, Analyzing Data, and Sharing or Publishing Data. Each rubric contains four to six rows of criteria and each criterion is measured by four different levels of mastery: Beginning, Developing, Improving, and Completion. The rubrics provide structure for an ePortfolio to be used in learning, teaching, and assessing RDM skills. The content of each rubric cell will assign a learning task, guide the acquisition of needed skills, and assess the accomplishments of new researchers taking part in an RDM seminar. Participants in the seminar will use their own research projects to plan, organize, analyze, and prepare for sharing data, and upload results to their own copy of the ePortfolio. The instructor for the seminar will use the content of rubric cells to develop assignments, teach relevant skills, and assess student success in mastering RDM skills. The Earth and Space Science rubrics are the first to be developed and will be followed by rubrics applicable to a number of other disciplines, as well as a rubric for interdisciplinary RDM. This presentation will review the Earth and Space Science rubrics, preview their use in an ePortfolio, and offer suggestions for others to prepare RDM rubrics for their own disciplines