Kyoto University · 물리·천문학
이 교수의 연구실은 지구 외부 방사선 벨트에서 태양풍과 상호작용하는 고에너지 전자의 가속 및 손실 메커니즘을 이해하기 위해 주로 비선형 웨이브-입자 상호작용, 특히 호이스틀러 모드 코러스 웨이브와 전자의 상호작용을 수치 시뮬레이션을 통해 연구합니다. 주요 연구 방향은 코러스 웨이브에 의한 메가전자의 비선형 가속, Landau 공명 메커니즘, 그리고 기울어진 전파 각도에서의 에너지 전달 메커니즘 분석입니다. 특히, 그린 함수 기반의 컨volution 기법을 활용해 전자 분포의 시간적 진화를 정량적으로 추적하는 데에 특화되어 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Abstract We perform test particle simulations for relativistic electrons interacting with a whistler mode chorus packet propagating at oblique angles. By confirming that the energy transport of oblique lower band chorus is nearly along the ambient magnetic field, we apply the gyroaveraging method in calculating equations of motion of electrons. We trace evolution of a delta function of relativistic electrons in a phase space of kinetic energy and equatorial pitch angle and obtain numerical Green
Abstract Nonlinear trapping of electrons via Landau resonance is an important mechanism of oblique whistler mode wave‐particle interactions. Electrons trapped by Landau resonance gain energies from waves. The Landau resonance velocity becomes very close to the group velocity of nearly parallel whistler mode waves at frequencies around half the electron gyrofrequency, resulting in a long interaction time and possible wave damping. We perform test particle simulations with parameters at L = 5 and
Abstract Nonlinear whistler mode wave‐particle interaction is one of the processes to generate relativistic electrons in the Earth's outer radiation belt. Applying test particle simulations with a pair of whistler mode chorus emissions, we traced a large number of electrons in various initial conditions along an magnetic field line to build a set of Green's functions for analyzing evolution of the electron distribution under the chorus emissions. Employing convolution integral for the Green's fu
Restrictions on the standard Shockley–Read–Hall (SRH) model in the recombination processes due to direct photoionization of the trapping centers have been theoretically studied. We find that, for photon energies even slightly in excess of the energy gap (i.e., ℏω≥Eg+0.01 eV) photoionization via defect states may normally be neglected in comparison with interband photogeneration, even in indirect semiconductors (e.g., n-type silicon doped with gold). For photon energies below Eg, the recombinatio
Abstract Energetic electron acceleration and precipitation in the Earth's outer radiation belt are highly associated with wave‐particle interactions between whistler mode chorus waves and electrons. We perform test particle simulations to investigate electrons interacting with parallel and oblique chorus emissions with maximum amplitude 2.1 nT and 370 pT at L = 4.5. We build up a database of Green's functions, which are treated as results of the input electrons interacting with one chorus emissi
Abstract We investigate the properties of whistler mode wave‐particle interactions at oblique wave normal angles to the background magnetic field. We find that electromagnetic energy of waves at frequencies below half the electron cyclotron frequency can flow nearly parallel to the ambient magnetic field. We thereby confirm that the gyroaveraging method, which averages the cyclotron motion to the gyrocenter and reduces the simulation from two‐dimensional to one‐dimensional, is valid for oblique
Abstract Electrons trapped in the Earth's magnetic field can be scattered by whistler mode chorus emissions and precipitate into the Earth's upper atmosphere. Whistler mode chorus waves propagating in the Earth's inner magnetic field are usually observed with oblique wave normal angles (WNAs). In this study, we apply 12 chorus wave models with four various WNA sets (the maximum WNA are 0°, 20°, 60°, and 90% of resonance cone angles) and three wave amplitude sets (the maximum wave magnetic fields
Earth and Space Science Open Archive This work has been accepted for publication in Journal of Geophysical Research - Space Physics. Version of RecordESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v1]Energetic electron precipitation induced by oblique whistler mode chorus emissionsAuthorsYi-KaiHsiehYoshiharuOmuraiDYukoKubotaSee all authors Yi-Kai Hsieh
Simulation data for paper entitled "Precipitation rates of electrons interacting with lower-band chorus emissions in the inner magnetosphere"
This dataset includes the simulation results of Green's function and convolution integrals for a paper submitted to JGR-Space Physics.
<p>Energetic electron acceleration and precipitation in the Earth's outer radiation belt are highly related to whistler mode chorus waves. We perform test particle simulations to investigate electron dynamics interacting with both parallel and oblique chorus emissions at L=4.5. We build up a database of the Green's functions for a large number of electrons interacting with whistler mode chorus emissions. The loss process of electron fluxes interacting with consecutive chorus emissi
