The precise magnetic field measurements by the Ørsted satellite revealed a distinct spatial variation of the eastward component residual (ΔBϕ) at mid and low latitudes on the dayside. This magnetic field variation was attributed to the interhemispheric field‐aligned currents (IHFACs) at mid and low latitudes based on its comparison with ground geomagnetic field variations. These IHFACs were found to flow from the summer hemisphere to the winter hemisphere in the dawn sector, and from the winter hemisphere to the summer hemisphere in the noon and the dusk sectors. These IHFACs flip their direction not at equinoxes but in May and November. The current intensity of the IHFACs is largest not at solstices but in February and August. The ground‐based geomagnetic field observations at 17 low latitude stations also support the seasonal dependence and local time distribution of the IHFACs.

[1] From the precise magnetic field measurements by the Oersted satellite at low altitudes over various local times, a distinct spatial variation at middle and low latitudes was detected in the eastward component residuals (ÁB f ) after the subtraction of a geomagnetic main field model. The average ÁB f decreases on the dayside as latitude increases, and it increases on the nightside. That is, the latitudinal structure of the ÁB f has a negative trend in the northward direction on the dayside and a positive trend on the nightside. The slope of the latitudinal profile of ÁB f is steep on both dayside and nightside under geomagnetically disturbed condition and has a high correlation with geomagnetic activity index such as the ap. These results strongly suggest the existence of a day-night net Birkeland current system that flows into the polar ionosphere on the dayside and flows out on the nightside. These net currents seem to distribute in wide local time range, and the center of the net currents is estimated to be around 1000 LT on the dayside and around 2200 LT on the nightside, which is essentially consistent with previous theoretical predictions and ground geomagnetic observations.

[1] The results of an analysis of the east-west magnetic variations at midlatitudes suggest that the net field-aligned currents, which are the integral of the downward and upward field-aligned currents along a meridian, are strongly controlled by the polar ionospheric conductivity. The east-west magnetic disturbances at midlatitudes are expected to be the magnetic effects of the net fieldaligned currents in the polar region. We have examined the relation between the auroral electrojet intensity represented by the auroral electrojet (AE) index and the net field-aligned current intensity represented by the east-west magnetic disturbances at midlatitudes. It is deduced from this analysis that the net field-aligned currents are upward on the nightside and downward on the dayside. It is also derived that the net upward field-aligned currents on the nightside are stronger in winter than in summer. This seasonal dependence can be explained by the seasonal variation of the polar cap ionospheric conductivity.

Gas flow control is important factor that influences the concentration of process gas and the pressure of the process chamber. In manufacturing processes that use metal organic (MO) gases, a system that controls the flow rate of MO gas must be developed to improve film performance and the reliability of film formation. We have developed a high temperature flow control system based on pressure measurements (HT-FCS) to control the flow rate of MO gas. Moreover, a liquid source control system that combines a HT-FCS and vaporizer was developed. Using this system, it was possible to control the flow rate of MO gas with high accuracy for extended periods. A flow control system that can supply MO gas with a stable flow rate by vaporizing MO material with the quantity needed at each time has been realized.

Abstract. We perform a case study of a favorable conjunction of an overpass of the Oersted satellite with the field-ofview of the SuperDARN Syowa East radar during an interval of the southward IMF B z . At the time, the radar observed an L-shell aligned boundary in the spectral width around the dayside ionosphere. Simultaneously, high-frequency (0.2-5 Hz) 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 B z conditions.