Full Particle Simulation of Whistler-Mode Triggered Falling-Tone Emissions in the Magnetosphere

We perform a one‐dimensional electromagnetic full particle simulation for triggered falling‐tone emissions in the Earth's magnetosphere. The equatorial region of the magnetosphere is modeled with a parabolic magnetic field approximation. The short whistler‐mode waves with a large amplitude are excited and propagate poleward from an artificial current oscillating with a constant frequency and amplitude. Following the excited waves, clear emissions are triggered with a falling frequency. Without the inhomogeneity of the background magnetic field, no triggered emission appears. The falling tone has several subpackets of amplitude and decreases the frequency in a stepwise manner. The positive resonant current formed by resonant electrons in the direction of the wave magnetic field clearly shows that an electron hill is formed in the phase space and causes the frequency decrease. The entrapping of the resonant electrons at the front of the packets and the decrease of the amplitude at the end of packets are essential for the generation of falling‐tone emissions. Each wavefront of the emission has a strongly negative resonant current −JE, which results in the wave growth. In the formation process of the resonant currents, we investigate the inhomogeneous factor S, which controls the nonlinear motion of the resonant electrons interacting with waves. The factor S consists of two terms, a frequency sweep rate and a gradient of the background magnetic field. The resonant current JE in the wave packet changes its sign from negative to positive as the packet moves away from the equator, terminating the wave growth

聖隷クリストファー大学看護基礎教育におけるシミュレーション教育の実践

紀要委員会企画Special Articles　本報告では、聖隷クリストファー大学看護基礎教育におけるシミュレーション教育の実践環境の構築、各領域における実践、教育力向上の取り組み、そして課題も含め今後の展望を報告する。本学は米国サミュエルメリット大学と2013 年に大学間交流協定を締結して以来、学生や教員が毎年、研修に赴きシミュレーション教育について学んできた。2016年に看護学部の教員有志によるワーキンググループが結成し、2017 年度より看護学部諮問委員会としてシミュレーション教育委員会が発足した。本学では、看護学部を中心にアクティブラーニングを実践するひとつの手法としてシミュレーション教育を検討し環境構築、研修会など学習の機会の提供、シミュレーションルームの機材および備品管理、シミュレーション教育実施の支援、広報活動など推進してきた。今後、シミュレーション教育を遂行する上で、以下の課題と展望がある。1．教育環境のさらなる充実、2．人員の確保、3．地域の拠点としてのシミュレーション教育の推進、4．活動のための運営資金の獲得である

Nonlinear wave growth theory of coherent hiss emissions in the plasmasphere

Article first published online: 29 SEP 2015Recent observations of plasmaspheric hiss emissions by the Van Allen Probes show that broadband hiss emissions in the plasmasphere comprise short-time coherent elements with rising and falling tone frequencies. Based on nonlinear wave growth theory of whistler mode chorus emissions, we have examined the applicability of the nonlinear theory to the coherent hiss emissions. We have generalized the derivation of the optimum wave amplitude for triggering rising tone chorus emissions to the cases of both rising and falling tone hiss elements. The amplitude profiles of the hiss emissions are well approximated by the optimum wave amplitudes for triggering rising or falling tones. Through the formation of electron holes for rising tones and electron hills for falling tones, the coherent waves evolve to attain the optimum amplitudes. An electromagnetic particle simulation confirms the nonlinear wave growth mechanism as the initial phase of the hiss generation process. We find very good agreement between the theoretical optimum amplitudes and the observed amplitudes as a function of instantaneous frequency. We calculate nonlinear growth rates at the equator and find that nonlinear growth rates for rising tone emissions are much larger than the linear growth rates. The time scales of observed hiss emissions also agree with those predicted by the nonlinear theory. Based on the theory, we can infer properties of energetic electrons generating hiss emissions in the equatorial region of the plasmasphere

Full Particle Simulation of Whistler‐Mode Triggered Falling‐Tone Emissions in the Magnetosphere

We perform a one‐dimensional electromagnetic full particle simulation for triggered falling‐tone emissions in the Earth's magnetosphere. The equatorial region of the magnetosphere is modeled with a parabolic magnetic field approximation. The short whistler‐mode waves with a large amplitude are excited and propagate poleward from an artificial current oscillating with a constant frequency and amplitude. Following the excited waves, clear emissions are triggered with a falling frequency. Without the inhomogeneity of the background magnetic field, no triggered emission appears. The falling tone has several subpackets of amplitude and decreases the frequency in a stepwise manner. The positive resonant current formed by resonant electrons in the direction of the wave magnetic field clearly shows that an electron hill is formed in the phase space and causes the frequency decrease. The entrapping of the resonant electrons at the front of the packets and the decrease of the amplitude at the end of packets are essential for the generation of falling‐tone emissions. Each wavefront of the emission has a strongly negative resonant current −JE, which results in the wave growth. In the formation process of the resonant currents, we investigate the inhomogeneous factor S, which controls the nonlinear motion of the resonant electrons interacting with waves. The factor S consists of two terms, a frequency sweep rate and a gradient of the background magnetic field. The resonant current JE in the wave packet changes its sign from negative to positive as the packet moves away from the equator, terminating the wave growth

Novel Platform for Regulation of Extracellular Vesicles and Metabolites Secretion from Cells Using a Multi-Linkable Horizontal Co-Culture Plate

Microfluidics is applied in biotechnology research via the creation of microfluidic channels and reaction vessels. Filters are considered to be able to simulate microfluidics. A typical example is the cell culture insert, which comprises two vessels connected by a filter. Cell culture inserts have been used for years to study cell-to-cell communication. These systems generally have a bucket-in-bucket structure and are hereafter referred to as a vertical-type co-culture plate (VTCP). However, VTCPs have several disadvantages, such as the inability to simultaneously observe samples in both containers and the inability of cell-to-cell communication through the filters at high cell densities. In this study, we developed a novel horizontal-type co-culture plate (HTCP) to overcome these disadvantages and confirm its performance. In addition, we clarified the migration characteristics of substances secreted from cells in horizontal co-culture vessels. It is generally assumed that less material is exchanged between the horizontal vessels. However, the extracellular vesicle (EV) transfer was found to be twice as high when using HTCP. Other merits include control of the degree of co-culture via the placement of cells. We believe that this novel HTCP container will facilitate research on cell-to-cell communication in various fields

An Extremely Young Protostellar Core, MMS 1/OMC-3: Episodic Mass Ejection History Traced by the Micro SiO Jet

We present ∼0.″2 (∼80 au) resolution observations of the CO(2–1) and SiO(5–4) lines made with the Atacama large millimeter/submillimeter array toward an extremely young intermediate-mass protostellar source ( t _dyn < 1000 yr), MMS 1 located in the Orion Molecular Cloud-3 region. We have successfully imaged a very compact CO molecular outflow associated with MMS 1, having deprojected lobe sizes of ∼1800 au (redshifted lobe) and ∼2800 au (blueshifted lobe). We have also detected an extremely compact (≲1000 au) and collimated SiO protostellar jet within the CO outflow. The maximum deprojected jet speed is measured to be as high as 93 km s ^−1 . The SiO jet wiggles and displays a chain of knots. Our detection of the molecular outflow and jet is the first direct evidence that MMS 1 already hosts a protostar. The position–velocity diagram obtained from the SiO emission shows two distinct structures: (i) bow shocks associated with the tips of the outflow, and (ii) a collimated jet, showing the jet velocities linearly increasing with the distance from the driving source. Comparisons between the observations and numerical simulations quantitatively share similarities such as multiple-mass ejection events within the jet and Hubble-like flow associated with each mass ejection event. Finally, while there is a weak flux decline seen in the 850 μ m light curve obtained with the James Clerk Maxwell Telescope/SCUBA 2 toward MMS 1, no dramatic flux change events are detected. This suggests that there has not been a clear burst event within the last 8 yr

Measurements of nongyrotropic electrons around the cyclotron resonance velocity in whistler-mode waves

The interaction between the electromagnetic field and charged particles is central for the collisionless plasma dynamics in space. Whistler-mode waves are one of the electromagnetic plasma waves, which play important roles in efficient pitch-angle scattering and acceleration of electrons in solar wind, collisionless shock waves as well as planetary magnetospheres. The nonlinear wave-particle interaction theory for coherent large amplitude waves predicts that electrons around resonance velocities exhibit nongyrotropy due to the phase trapping motion around them and the nongyrotropic electrons exchange energy and momentum with the waves in the presence of an appropriate inhomogeneity. In this presentation, we show observational results of nongyrotropic electrons around the cyclotron resonance velocity using the data obtained by the Magnetospheric Multiscale (MMS) spacecraft during a whistler-mode wave (about 200 Hz) event around the magnetosheath-side separatrix of the dayside magnetopause reconnection. On the basis of measurements by the Fast Plasma Investigation Dual Electron Spectrometer (FPI-DES), the search-coil magnetometer (SCM), and the Electron Drift Instruments (EDI), the relative phase angle of the electron hole to the magnetic field of the whistler-mode wave agrees well with the prediction by the nonlinear theory, and this type of the electrons appeared only around the cyclotron resonance velocity. The electron flux at the hole was about 40% lower than that at the peak in the most pronounced case. This result provides evidence of locally ongoing nonlinear wave-particle interaction between the electrons and whistler-mode waves, and proves that the nonlinear wave growth occurs around the dayside reconnection