• 제목/요약/키워드: EMIC

검색결과 27건 처리시간 0.022초

Pc1/EMIC waves observed at subauroral latitude during sudden magnetospheric compressions

  • 김관혁;;이동훈;권혁진;이은상
    • 천문학회보
    • /
    • 제37권2호
    • /
    • pp.117.2-117.2
    • /
    • 2012
  • It is generally accepted that sudden compressions of the magnetosphere cause electromagnetic ion cyclotron (EMIC) wave growth by increasing the proton temperature anisotropy. These compression-associated EMIC waves are expected to be on higher latitudes (i.e., higher-L regions close to the magnetopause). In this study we examine Pc1 pulsations, which are believed to be generated by the EMIC instability, observed at subauroral latitude near the nominal plasmapause when the magnetosphere is suddenly compressed by solar wind dynamic pressure variations, using induction magnetometer data obtained from Athabasca, Canada (geomagnetic latitude = 61.7 N, L ~ 4.5). We identified 9 compression-associated Pc1 waves with frequencies of ~0.5-2.0 Hz. The wave activity appears in the horizontal H (positive north) and D (positive eastward) components. All of events show low coherence between H and D components. This indicates that the Pc1 pulsations in H and D oscillate with a different frequency. Thus, we cannot determine the polarization state of the waves. We will discuss the occurrence location of compression-associated Pc1 pulsations, their spectral structure, and wave properties.

  • PDF

Structural Analysis of Species in NbCI5-EMIC Room-Temperature Molten Salt with Raman Spectroscopic Measurement and Ab Initio Molecular Orbital Calculation

  • Koura, Nobuyuki;Matsuzawa, Hidenori;Kato, Tomoki;Idemoto, Yasushi;Matsumoto, Futoshi
    • 전기화학회지
    • /
    • 제5권4호
    • /
    • pp.183-188
    • /
    • 2002
  • The structure of species formed in $NbCI_5-I-ethyl-3-methylimidazolium$ chloride (EMIC) room-temperature molten salt (RTMS) was examined with the Raman spectroscopic measurement and ab initio molecular orbital calculation. The equilibrium structures of $NbCl_5,\;NbCl_6^-,\;Nb_2CI_{10},\;Nb_2CI_{11}^-,\;Nb_3CI_6^-,\;NbCI_6^--EMI^+\;(in\;which\;NbCI_6^-$ anion approaches $EMI^+$ cation with strong interaction) and $Nb_2CI_{11}^--EMI^+$ were obtained with the HF/LANL2DZ level of calculation. The harmonic frequencies at each equilibrium structure were compared with Raman spectra. The harmonic frequencies of $NbCI_6^--EMI^+,\; Nb_2CI_{11}^--EMI^+,\;and\;Nb_2CI_{10}$ were in good agreement with the Raman spectra of RTMS melts. In the $NbCI_5-EMIC RTMS$, the main species were $NbCI_6^-\;and\;EMI^+$. In the $NbCl_5-EMIC$ RTMS added $NbCl_5\;over\;50mol\%$, small amount of $Nb_2CI_{11}^-\;and\; Nb_2CI_{10}$ were also formed. The structures of anions and cation in the RTMS distorted from free ions with Coulomb force.

Harmony through Holistic Engagement: An Emic Model of Greater East Asian Regionalism

  • von Feigenblatt, Otto F.
    • Journal of Contemporary Eastern Asia
    • /
    • 제12권2호
    • /
    • pp.61-87
    • /
    • 2013
  • This study applies grounded theory to develop an emic substantive theory of regional integration in Greater East Asia. The role of norms and policies is explored through discursive content analysis of a wide theoretical sample of official elite policy statements dealing with regionalism and related policy areas. A resulting model of regional integration titled "Harmony through Holistic Engagement" is then discussed in relation to the etic consensus on the phenomenon. The study concludes that the etic consensus on the nature of regional integration in Greater East Asia greatly differs from the results of an emic approach and thus reflects a normative consensus rather than a descriptive reality.

Radiation belt electron losses induced by wave-particle interactions

  • Summers, Danny
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
    • /
    • 한국우주과학회 2009년도 한국우주과학회보 제18권2호
    • /
    • pp.32.2-32.2
    • /
    • 2009
  • We examine cyclotron resonant interactions of radiation belt electrons with VLF chorus, plasmaspheric ELF hiss and electromagnetic ion cyclotron (EMIC) waves. Bounce-averaged diffusion rates depend on wave mode, equatorial pitch-angle, electron energy and L-shell. As well, diffusion rates can be sensitive to the latitudinal distributions of particle density and wave power. For different configurations of the plasmasphere, we calculate electron precipitation loss timescales due to combined scattering by VLF chorus, ELF hiss and EMIC waves.

  • PDF

Limitations of Electromagnetic Ion Cyclotron Wave Observations in Low Earth Orbit

  • Hwang, Junga;Kim, Hyangpyo;Park, Jaeheung;Lee, Jaejin
    • Journal of Astronomy and Space Sciences
    • /
    • 제35권1호
    • /
    • pp.31-37
    • /
    • 2018
  • Pc1 pulsations are geomagnetic fluctuations in the frequency range of 0.2 to 5 Hz. There have been several observations of Pc1 pulsations in low earth orbit by MAGSAT, DE-2, Viking, Freja, CHAMP, and SWARM satellites. However, there has been a clear limitation in resolving the spatial and temporal variations of the pulsation by using a single-point observation by a single satellite. To overcome such limitations of previous observations, a new space mission was recently initiated, using the concept of multi-satellites, named the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE). The SNIPE mission consists of four nanosatellites (~10 kg), which will be launched into a polar orbit at an altitude of 600 km (TBD) in 2020. Four satellites will be deployed in orbit, and the distances between each satellite will be controlled from 10 to 1,000 km by a high-end formation-flying algorithm. One of the possible science targets of the SNIPE mission is observing electromagnetic ion cyclotron (EMIC) waves. In this paper, we report on examples of observations, showing the limitations of previous EMIC observations in low earth orbit, and suggest possibilities to overcome those limitations through a new mission.

Incorporation of Electromagnetic Ion cyclotron waveinto Radiation Belt environment model

  • 강석빈;최은진;황정아;김경찬;이재진;;민경욱;최정임;박영득
    • 천문학회보
    • /
    • 제37권2호
    • /
    • pp.132.1-132.1
    • /
    • 2012
  • Radiation Belt Environment (RBE) model has developed to understand radiation belt dynamics as it considers whistler mode hiss and chorus waves which is responsible for relativistic electron acceleration and precipitation. Recently, many studies on electron loss by pitch-angle scattering have reported that elctromagnetic ion cyclotron (EMIC) wave is also responsible for main loss mechanism in dusk and equatorial regeion. Here, we attempt to incorporate EMIC into RBE model simulation code to understand more detailed physical dynamics in Radiation belt environemnt. We compare this developed model to data during storm events where both of electron loss and EMIC waves were detected.

  • PDF

에이전트를 활용한 응급의료지도 지원시스템 설계에 관한 연구 (A Study on Design of Medical Advice Support System in Emergency using Agent System)

  • 김경환
    • 한국정보시스템학회지:정보시스템연구
    • /
    • 제19권3호
    • /
    • pp.263-278
    • /
    • 2010
  • Emergency Medical Service(EMS) requires a system that supports the communication between emergency medical technicians (EMT)s and the doctor in the emergency department. Because the rapid triage and on-site treatment of patients need doctor's medical advice. However, a system to assist the doctor assign for medical advice does not exist in Korea. This paper suggests a medical advice support system that focuses on appropriate doctor assign and real-time communication among the ambulance, the Emergency Medical Information Center (EMIC), and the doctor using an agent system. We expect that the system can help to solve the problems affecting prehospital EMS and improve its general quality.

PIC simulation study of the turbulence of the Alfven ion-cyclotron waves induced by electromagnetic ion-cyclotron instability

  • Kaang, Helen H.;Ryu, Chang-Mo;Mok, Chinook;Rha, Ki-Cheol
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
    • /
    • 한국우주과학회 2011년도 한국우주과학회보 제20권1호
    • /
    • pp.29.3-29.3
    • /
    • 2011
  • The turbulence in the nonlinear regime of the electromagnetic ion-cyclotron (EMIC) instability are investigated via a particle-in-cell (PIC) simulation. EMIC instability arises from anisotropic ion temperature and excites the Alfven ion-cyclotron (AIC) waves. The excited AIC waves undergo inverse-cascade via the nonlinear wave interaction of two AIC and one ion density modes. Induced ion density modes are the normal and second harmonic ion-acoustic (IA) waves. They have the same group velocity, but the second harmonic IA mode only generates the longitudinal electric field.

  • PDF

Simulation study on the nonlinear evolution of EMIC instability

  • 라기철;류창모
    • 천문학회보
    • /
    • 제37권2호
    • /
    • pp.119.2-119.2
    • /
    • 2012
  • Charged particle energization is an outstanding problem in space physics. This paper investigates the nonlinear dynamics of Alfve'n-cyclotron waves accompanying particle heating processes and the drift Alfv'en-cyclotron (or EMIC) instability associated with a current disruption event on 29 January 2008 observed with THEMIS satellite by means of a particle-in-cell simulation. The simulation shows that the drift Alfv'en-cyclotron instabilities are excited in two regimes, a relatively low frequency mode propagating in a quasi-perpendicular direction while the second high-frequency branch propagating in a predominantly parallel propagation direction, which is consistent with observation as well as earlier theories. It is shown that parametric decay processes lead to an inverse cascade of Alfv'en-cyclotron waves and the generation of ion-acoustic waves by decay instability. It is also shown that the nonlinear decay processes are accompanied by small perpendicular heating and parallel cooling of the protons, and a pronounced parallel heating of the electrons.

  • PDF

문화 변수가 협상 윤리에 미치는 영향 '체면'과 홉스테드 변수의 비교 (The Effect of Cultural Predictors on Perceived Ethicality of Negotiation Behavior A Comparison of 'Chemyon' and Hofstede's Cultural Dimensions)

  • 김영욱;양정은
    • 한국언론정보학보
    • /
    • 제46권
    • /
    • pp.212-244
    • /
    • 2009
  • 이 연구는 우리나라 협상자들이 가지는 인구학적 특성과 문화 가치가 비윤리적 협상 전략에 대한 평가와 사용의도에 미치는 영향을 연구한 것이다. 협상자의 문화 가치에 따라 전통적 경쟁협상, 상대 네트워크 공격, 거짓약속, 허위정보 전달 및 비윤리적 정보 수집의 다섯 가지 비윤리적 전략에 대한 평가와 사용의도에 차이가 나타나는지 살펴보았다. 특히 협상자의 문화 가치를 측정함에 있어 보편적(etic) 문화 가치로 인정되는 홉스테드(Hofstede) 문화변수와 우리나라 고유의 문화 변수인 '체면'을 함께 고려하여 문화 변수들 간의 상대적 설명력을 비교하였다. 연구결과, 인구학적 특성과 문화 가치는 모두 비윤리적 협상 전략에 대한 평가에 영향을 주고 있었다. 인구학적 특성의 경우, 연령과 경력은 유의미한 결과를 나타냈으나 성별과 협상 스타일은 유의미한 영향을 미치지 않았다. 문화 변수의 경우, 체면 변수의 설명력이 홉스테드의 문화변수보다 높게 나타나는 경향을 보여, 비윤리적 협상 전략에 대한 우리나라 협상자들의 인식과 태도에 체면이 중요한 영향을 미치고 있다는 것을 확인할 수 있었다. 연구 결과를 바탕으로 문화 현상에 대한 에믹(emic) 접근과 에틱(etic) 접근의 유용성에 대해 논의하였다.

  • PDF