Heating and current generation due to the lower hybrid wave are studied using particle simulation. In contrast with previous work, where only a single mode is treated, the main interest of this work is focused on the physical problems of a propagation cone consisting of many Fourier‐expanded modes. It is found that the trajectory of the propagation cone is well described up to the lower hybrid resonance layer using both the cold plasma approximation and the WKB method. An ion cross‐field drift due to the ponderomotive force is observed. A main discovery of this work is that the modes in the upper portion of the spectrum of the antenna play a key role in the creation of the ion high‐energy tail. This process cannot be explained by the linear theory and is called the cascade process judging from the time variation of the damping of each mode. The particle model is significantly improved using the elongated grid and the quadratic spatial interpolation. Applications of this model to simulations of other probl...
{"title":"Energy and Momentum Deposition to Plasmas due to the Lower Hybrid Wave by a Finite Source","authors":"N. Nakajima, H. Abe, R. Itatani","doi":"10.1063/1.863729","DOIUrl":"https://doi.org/10.1063/1.863729","url":null,"abstract":"Heating and current generation due to the lower hybrid wave are studied using particle simulation. In contrast with previous work, where only a single mode is treated, the main interest of this work is focused on the physical problems of a propagation cone consisting of many Fourier‐expanded modes. It is found that the trajectory of the propagation cone is well described up to the lower hybrid resonance layer using both the cold plasma approximation and the WKB method. An ion cross‐field drift due to the ponderomotive force is observed. A main discovery of this work is that the modes in the upper portion of the spectrum of the antenna play a key role in the creation of the ion high‐energy tail. This process cannot be explained by the linear theory and is called the cascade process judging from the time variation of the damping of each mode. The particle model is significantly improved using the elongated grid and the quadratic spatial interpolation. Applications of this model to simulations of other probl...","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"66 1","pages":"1-64"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78589711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1981-10-01DOI: 10.1103/PHYSREVLETT.48.1022
T. Fujimoto, T. Kato
It is shown that, in dense plasmas, dielectronic capture into doubly excited ionic states followed by the ladderlike excitation-ionization chain becomes important in the excitation-ionization process of ions. For an example of a hydrogenlike ion, its contribution to the excitation 1s..-->..2s, 2p and also to the ionization has been evaluated by the method of the quasisteady-state solution to the rate equations. The increase is found to be substantial, i.e., by more than a factor of 2 both for the excitation and ionization rate coefficients.
{"title":"New Excitation and Ionization Mechanism of Ions in Dense Plasmas : The Role of Autoionizing States","authors":"T. Fujimoto, T. Kato","doi":"10.1103/PHYSREVLETT.48.1022","DOIUrl":"https://doi.org/10.1103/PHYSREVLETT.48.1022","url":null,"abstract":"It is shown that, in dense plasmas, dielectronic capture into doubly excited ionic states followed by the ladderlike excitation-ionization chain becomes important in the excitation-ionization process of ions. For an example of a hydrogenlike ion, its contribution to the excitation 1s..-->..2s, 2p and also to the ionization has been evaluated by the method of the quasisteady-state solution to the rate equations. The increase is found to be substantial, i.e., by more than a factor of 2 both for the excitation and ionization rate coefficients.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"57 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91316020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1981-10-01DOI: 10.1103/PHYSREVLETT.47.1902
M. Nakamura, T. Cho, S. Kubo, T. Shimozuma, H. Kawai, Y. Yamazaki, T. Maekawa, Y. Terumichi, Shigetoshi Tanaka, Y. Hamada
By injecting rf power P/sub rf/ near the lower hybrid frequency into an Ohmically heated plasma near the end of tokamak discharge in the WT-2, an rf-driven current-sustained plasma is produced and continues to exist during the rf injection period, the toroidal current (I/sub p/approx.10 kA) being generated by the lower hybrid wave only without the Ohmic power. The efficiency of rf-driven current generation is high and attains I/sub p//P/sub rf/roughly-equal0.9 kA/kW at the plasma density n/sub e/approx. =1.4 x 10/sup 12/ cm/sup -3/, with somewhat lower efficiency at higher density.
在WT-2中，在托卡马克放电结束时，向欧姆加热的等离子体中注入较低混合频率附近的射频功率P/sub rf/，产生射频驱动的持续电流等离子体，并在射频注入期间持续存在，环形电流(I/sub rf/)约为。10 kA)仅由低杂波产生，没有欧姆功率。射频驱动的电流产生效率高，在等离子体密度n/sub / e/左右时达到I/sub p// p/ sub rf/约等于0.9 kA/kW。=1.4 x 10/sup 12/ cm/sup -3/，密度越大效率越低。
{"title":"TOROIDAL PLASMA CURRENT SUSTAINMENT BY LOWER HYBRID WAVES IN THE WT-2 TOKAMAK","authors":"M. Nakamura, T. Cho, S. Kubo, T. Shimozuma, H. Kawai, Y. Yamazaki, T. Maekawa, Y. Terumichi, Shigetoshi Tanaka, Y. Hamada","doi":"10.1103/PHYSREVLETT.47.1902","DOIUrl":"https://doi.org/10.1103/PHYSREVLETT.47.1902","url":null,"abstract":"By injecting rf power P/sub rf/ near the lower hybrid frequency into an Ohmically heated plasma near the end of tokamak discharge in the WT-2, an rf-driven current-sustained plasma is produced and continues to exist during the rf injection period, the toroidal current (I/sub p/approx.10 kA) being generated by the lower hybrid wave only without the Ohmic power. The efficiency of rf-driven current generation is high and attains I/sub p//P/sub rf/roughly-equal0.9 kA/kW at the plasma density n/sub e/approx. =1.4 x 10/sup 12/ cm/sup -3/, with somewhat lower efficiency at higher density.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"56 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83929345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A theoroetical model of the triggering of a solar flare by magnetosonic waves in a neutral sheet plasma is discussed. It is shown that the ponderomotive force due to the magnetosonic waves strongly excites the plamsa convection flow in the magnetic neutral sheet which in turn enhances the tearing instability. The system of basic equations for the tearing mode, including the time-averaged nonlinear effects due to the growth time of the instability is shortened to about 100 s for reasonable magnetosonic wave intensity.
{"title":"A Triggering of Solar Flare by Magnetosonic Waves in a Neutral Sheet Plasma","authors":"J. Sakai, H. Washimi","doi":"10.1086/160129","DOIUrl":"https://doi.org/10.1086/160129","url":null,"abstract":"A theoroetical model of the triggering of a solar flare by magnetosonic waves in a neutral sheet plasma is discussed. It is shown that the ponderomotive force due to the magnetosonic waves strongly excites the plamsa convection flow in the magnetic neutral sheet which in turn enhances the tearing instability. The system of basic equations for the tearing mode, including the time-averaged nonlinear effects due to the growth time of the instability is shortened to about 100 s for reasonable magnetosonic wave intensity.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"30 1","pages":"1-30"},"PeriodicalIF":0.0,"publicationDate":"1981-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85951387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Total charge transfer cross sections are calculated for the collisions of Li 3+ and Be 4+ ions with H(1s) atoms in the low energy region ( E <25 keV/amu). The perturbed-stationaly-state method in the impact parameter approximation is used with a basis set of adiabatic one-electron two-center molecular orbitals. For the Li 3+ -H system, a reasonable agreement is found between the present calculation and the recent experiment.
{"title":"Charge Transfer in Collisions of Li^ and Be^ ions with Atomic Hydrogen at Low Impact Energy","authors":"T. Ohyama, Y. Itikawa","doi":"10.1143/JPSJ.51.2982","DOIUrl":"https://doi.org/10.1143/JPSJ.51.2982","url":null,"abstract":"Total charge transfer cross sections are calculated for the collisions of Li 3+ and Be 4+ ions with H(1s) atoms in the low energy region ( E <25 keV/amu). The perturbed-stationaly-state method in the impact parameter approximation is used with a basis set of adiabatic one-electron two-center molecular orbitals. For the Li 3+ -H system, a reasonable agreement is found between the present calculation and the recent experiment.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"56 1","pages":"1-20"},"PeriodicalIF":0.0,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76192853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Iwama, A. Inoue, T. Tsukishima, M. Sato, K. Kawahata, K. Sakai
A new procedure for the maximum entropy spectral estimation is studied for the purpose of data processing in Fourier transform spectroscopy. The fitting of the autoregressive model to the interferogram is examined under a least‐squares criterion based on the Yule‐Walker equations. A practical criterion is suggested for selecting the model order. The principal advantage of the new procedure lies in the enhanced frequency resolution, particularly for small values of the maximum optical path difference of the interferogram. The usefulness of the procedure is ascertained by some numerical simulations and further by experiments with respect to a highly coherent submillimeter wave and the electron cyclotron emission from a stellarator plasma.
{"title":"Least Squares Autoregressive (Maximum Entropy) Spectral Estimation for Fourier Spectroscopy and its Application to the Electron Cyclotron Emission from Plasma","authors":"N. Iwama, A. Inoue, T. Tsukishima, M. Sato, K. Kawahata, K. Sakai","doi":"10.1063/1.329527","DOIUrl":"https://doi.org/10.1063/1.329527","url":null,"abstract":"A new procedure for the maximum entropy spectral estimation is studied for the purpose of data processing in Fourier transform spectroscopy. The fitting of the autoregressive model to the interferogram is examined under a least‐squares criterion based on the Yule‐Walker equations. A practical criterion is suggested for selecting the model order. The principal advantage of the new procedure lies in the enhanced frequency resolution, particularly for small values of the maximum optical path difference of the interferogram. The usefulness of the procedure is ascertained by some numerical simulations and further by experiments with respect to a highly coherent submillimeter wave and the electron cyclotron emission from a stellarator plasma.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"16 1","pages":"1-46"},"PeriodicalIF":0.0,"publicationDate":"1981-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82224691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1981-01-01DOI: 10.1007/978-3-642-81778-6_13
H. Mori
{"title":"Evolution of Chaos and Power Spectra in One-Dimensional Maps","authors":"H. Mori","doi":"10.1007/978-3-642-81778-6_13","DOIUrl":"https://doi.org/10.1007/978-3-642-81778-6_13","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"39 1","pages":"115-117"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85626357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1981-01-01DOI: 10.1007/978-94-009-8440-0_21
K. Minami
{"title":"Numerical Calculations on the Propagation of Microwaves in Highly Over-Dense Magnetized Plasmas","authors":"K. Minami","doi":"10.1007/978-94-009-8440-0_21","DOIUrl":"https://doi.org/10.1007/978-94-009-8440-0_21","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"95 1","pages":"231-238"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86283601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1980-11-01DOI: 10.1088/0032-1028/24/12/005
O. Fukumasa, R. Itatani
Suppression of the beam-excited electron wave in a bounded system is investigated in connection with the beam distribution function. Wave suppression has two different processes depending on whether injected beams are reflected at the other end or not. In the absence of reflected beam electrons, deformation of the beam distribution function is observed in relation to the suppression of the electron wave. However, when beam electrons are reflected, the external wave suppresses the electron wave but distribution function shows no appreciable change. By using the method of partial simulation, interaction between two waves in the bounded system including nonlinear motions of beam electrons is studied numerically. Qualitative agreement between experimental and numerical results is obtained.
{"title":"Suppression of Beam-Excited Electron Waves by an Externally Applied RF Signal","authors":"O. Fukumasa, R. Itatani","doi":"10.1088/0032-1028/24/12/005","DOIUrl":"https://doi.org/10.1088/0032-1028/24/12/005","url":null,"abstract":"Suppression of the beam-excited electron wave in a bounded system is investigated in connection with the beam distribution function. Wave suppression has two different processes depending on whether injected beams are reflected at the other end or not. In the absence of reflected beam electrons, deformation of the beam distribution function is observed in relation to the suppression of the electron wave. However, when beam electrons are reflected, the external wave suppresses the electron wave but distribution function shows no appreciable change. By using the method of partial simulation, interaction between two waves in the bounded system including nonlinear motions of beam electrons is studied numerically. Qualitative agreement between experimental and numerical results is obtained.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"92 1","pages":"1-54"},"PeriodicalIF":0.0,"publicationDate":"1980-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91051782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1980-09-01DOI: 10.1103/PHYSREVLETT.45.1626
Y. Nishida, T. Nagasawa
The nonlinear evolution of oblique collisions are investigated experimentally on plane ion-acoustic solitons in two-dimensional space. Many of the observed characteristics of inelastic collisions of solitons are found to be similar to those of resonance interactions described by nonlinear ion-acoustic waves.
{"title":"Oblique Collision of Plane Ion-Acoustic Solitons","authors":"Y. Nishida, T. Nagasawa","doi":"10.1103/PHYSREVLETT.45.1626","DOIUrl":"https://doi.org/10.1103/PHYSREVLETT.45.1626","url":null,"abstract":"The nonlinear evolution of oblique collisions are investigated experimentally on plane ion-acoustic solitons in two-dimensional space. Many of the observed characteristics of inelastic collisions of solitons are found to be similar to those of resonance interactions described by nonlinear ion-acoustic waves.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"43 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"1980-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91132660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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