M. Hasegawa, K. Narihara, Y. Tomita, T. Tsuzuki, A. Mohri
Measurement of X-ray bremsstrahlung emitted from REB rings formed in SPAC-Vl toroidal device elucidated that major radius compression of the ring raises energies of the ring electrons. At the compression ratio of 2.0, the ring current rose from 24 kA to 50 kA. The highest energy of electrons that was estimated by hard X-ray spectrum measurement increased from ∼1 MeV to ∼2 MeV. The energy distribution of REB was broadly spread. During the compression, the current of ring I R and the major radius R are governed by the relation I R · R =const. Some discussions on this relation are given in which energy spread of the beam electrons and the change in the magnetic flux enclosed by the ring are taken into consideration.
{"title":"Electron energy increase of an REB-ring by major radius compression","authors":"M. Hasegawa, K. Narihara, Y. Tomita, T. Tsuzuki, A. Mohri","doi":"10.1143/JPSJ.56.1394","DOIUrl":"https://doi.org/10.1143/JPSJ.56.1394","url":null,"abstract":"Measurement of X-ray bremsstrahlung emitted from REB rings formed in SPAC-Vl toroidal device elucidated that major radius compression of the ring raises energies of the ring electrons. At the compression ratio of 2.0, the ring current rose from 24 kA to 50 kA. The highest energy of electrons that was estimated by hard X-ray spectrum measurement increased from ∼1 MeV to ∼2 MeV. The energy distribution of REB was broadly spread. During the compression, the current of ring I R and the major radius R are governed by the relation I R · R =const. Some discussions on this relation are given in which energy spread of the beam electrons and the change in the magnetic flux enclosed by the ring are taken into consideration.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"3 1","pages":"1-32"},"PeriodicalIF":0.0,"publicationDate":"1987-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84530200","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}
By means of the two‐fluid model, the kink stability of a long thin field‐reversed ion layer immersed in a dense low‐temperature background plasma is studied theoretically. The two‐fluid variational quadratic form with the assumption of rigid displacements in the radial direction yields a new kink stability condition that includes the effect of the nonzero real frequency of the modes, which results from the inertia of the ion layer. Although it was neglected in previous analyses, this effect is essential to explain the numerical results of Harned [Phys. Fluids 25, 1915 (1982)]. As the ratio of the density of the background plasma to that of the ion layer increases, this new kink stability condition reduces to the conventional condition. The physical mechanism for the kink instability is discussed by means of an analogy with the electrostatic two‐stream instability.
{"title":"Kink Stability of Long Ion Layers","authors":"A. Ishida","doi":"10.1063/1.865551","DOIUrl":"https://doi.org/10.1063/1.865551","url":null,"abstract":"By means of the two‐fluid model, the kink stability of a long thin field‐reversed ion layer immersed in a dense low‐temperature background plasma is studied theoretically. The two‐fluid variational quadratic form with the assumption of rigid displacements in the radial direction yields a new kink stability condition that includes the effect of the nonzero real frequency of the modes, which results from the inertia of the ion layer. Although it was neglected in previous analyses, this effect is essential to explain the numerical results of Harned [Phys. Fluids 25, 1915 (1982)]. As the ratio of the density of the background plasma to that of the ion layer increases, this new kink stability condition reduces to the conventional condition. The physical mechanism for the kink instability is discussed by means of an analogy with the electrostatic two‐stream instability.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"27 1","pages":"1-28"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78150777","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 : 1986-08-01DOI: 10.1016/0375-9601(87)90042-9
K. Masai, T. Kato
{"title":"ELECTRON DENSITY DIAGNOSTICS BY FE XXII LINE INTENSITY RATIO","authors":"K. Masai, T. Kato","doi":"10.1016/0375-9601(87)90042-9","DOIUrl":"https://doi.org/10.1016/0375-9601(87)90042-9","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"29 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75742619","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 relativistic theory for a nonlinear magnetosonic wave propagating perpendicularly to a magnetic field is developed. On the basis of a relativistic two‐fluid cold plasma model, the structure of a stationary magnetosonic wave is studied. Relativistic effects become important for the parameter regime ωce/ωpe≳1, because the fluid electron velocity perpendicular to a magnetic field and parallel to the wave front takes values close to the speed of light for such plasma parameters. It is found that there exists a stationary solitary wave solution even in the relativistic model. Some properties of the solitary wave, such as the soliton width, are discussed.
{"title":"A Solitary Wave of a Relativistic Magnetosonic Wave Propagating Perpendicularly to a Magnetic Field","authors":"Y. Ohsawa","doi":"10.1063/1.865540","DOIUrl":"https://doi.org/10.1063/1.865540","url":null,"abstract":"A relativistic theory for a nonlinear magnetosonic wave propagating perpendicularly to a magnetic field is developed. On the basis of a relativistic two‐fluid cold plasma model, the structure of a stationary magnetosonic wave is studied. Relativistic effects become important for the parameter regime ωce/ωpe≳1, because the fluid electron velocity perpendicular to a magnetic field and parallel to the wave front takes values close to the speed of light for such plasma parameters. It is found that there exists a stationary solitary wave solution even in the relativistic model. Some properties of the solitary wave, such as the soliton width, are discussed.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"4 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"1986-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86169707","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}
Theoretical and numerical analyses are carried out for plasma heating and proton acceleration (V x B) due to magnetosonic shock waves (MSW) in the solar plasma. A simple model is developed for V x B acceleration by examining a single-particle orbit in a high-amplitude monochromatic electrostatic wave moving in a direction perpendicular to an external magnetic field. The particle can attain the E x B drift velocity. The model is used to derive the maximum velocity a particle can attain when driven by quasi-parallel and quasi-perpendicular MSW. Acceleration is found to be significantly stronger witn the latter, as is demonstrated with results of a 2.5 dimension simulation of acceleration by a quasi-perpendicular MSW. Implications of the results for modeling coronal heating and proton acceleration by MSWs produced by solar flares are discussed. 39 references.
对太阳等离子体中磁声激波(MSW)引起的等离子体加热和质子加速(V x B)进行了理论和数值分析。通过检测沿垂直于外磁场方向运动的高振幅单色静电波中的单粒子轨道，建立了一个简单的V x B加速度模型。粒子可以达到E × B漂移速度。利用该模型推导了在准平行和准垂直固体垃圾驱动下粒子所能达到的最大速度。通过准垂直的固体固体垃圾进行的2.5维加速度模拟结果表明，在后者内，加速度明显更强。讨论了模拟太阳耀斑产生的固体固体水对日冕加热和质子加速的影响。39岁的引用。
{"title":"Non-stochastic prompt proton acceleration by fast magnetosonic shocks in the solar plasma","authors":"J. Sakai, Y. Ohsawa","doi":"10.1086/164983","DOIUrl":"https://doi.org/10.1086/164983","url":null,"abstract":"Theoretical and numerical analyses are carried out for plasma heating and proton acceleration (V x B) due to magnetosonic shock waves (MSW) in the solar plasma. A simple model is developed for V x B acceleration by examining a single-particle orbit in a high-amplitude monochromatic electrostatic wave moving in a direction perpendicular to an external magnetic field. The particle can attain the E x B drift velocity. The model is used to derive the maximum velocity a particle can attain when driven by quasi-parallel and quasi-perpendicular MSW. Acceleration is found to be significantly stronger witn the latter, as is demonstrated with results of a 2.5 dimension simulation of acceleration by a quasi-perpendicular MSW. Implications of the results for modeling coronal heating and proton acceleration by MSWs produced by solar flares are discussed. 39 references.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"26 1","pages":"1-32"},"PeriodicalIF":0.0,"publicationDate":"1986-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76725060","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 Korteweg–de Vries equation that is applicable to both the nonlinear magnetosonic fast and slow waves is derived from a two‐fluid model with finite ion and electron pressures. As in the cold plasma theory, the fast wave has a critical angle θc. For propagation angles greater than θc (quasiperpendicular propagation), the fast wave has a positive soliton, whereas for angles smaller than θc, it has a negative soliton. Finite β effects decrease the value of θc. The slow wave has a positive soliton for all angles of propagation. The magnitude of resonant ion acceleration (the vp×B acceleration) by the nonlinear fast and slow waves is evaluated. In the fast wave, the electron pressure makes the acceleration stronger for all propagation angles. The decrease in θc resulting from finite β effects results in broadening of the region of strong acceleration. It is also found that fairly strong ion acceleration can occur in the nonlinear slow wave in high β plasmas. The possibility of unlimited acceleration of ion...
{"title":"Theory for Resonant Ion Acceleration by Nonlinear Magnetosonic Fast and Slow Waves in Finite β Plasmas","authors":"Y. Ohsawa","doi":"10.1063/1.865614","DOIUrl":"https://doi.org/10.1063/1.865614","url":null,"abstract":"A Korteweg–de Vries equation that is applicable to both the nonlinear magnetosonic fast and slow waves is derived from a two‐fluid model with finite ion and electron pressures. As in the cold plasma theory, the fast wave has a critical angle θc. For propagation angles greater than θc (quasiperpendicular propagation), the fast wave has a positive soliton, whereas for angles smaller than θc, it has a negative soliton. Finite β effects decrease the value of θc. The slow wave has a positive soliton for all angles of propagation. The magnitude of resonant ion acceleration (the vp×B acceleration) by the nonlinear fast and slow waves is evaluated. In the fast wave, the electron pressure makes the acceleration stronger for all propagation angles. The decrease in θc resulting from finite β effects results in broadening of the region of strong acceleration. It is also found that fairly strong ion acceleration can occur in the nonlinear slow wave in high β plasmas. The possibility of unlimited acceleration of ion...","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"80 1","pages":"1-39"},"PeriodicalIF":0.0,"publicationDate":"1985-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82588530","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}
T. Matsuzawa, A. Takahashi, K. Masugata, M. Ito, Masao Matsui, K. Yatsui
A time‐resolvable Thomson‐parabola spectrometer is developed employing a microchannel‐plate image intensifier, which acts as a high‐speed shutter (∼5 ns) by gating the applied voltage. Using such a spectrometer, we have achieved the measurement of temporal behavior of beam energy for various ion species of an intense pulsed ion beam extracted from a dual‐current‐feed magnetically insulated diode. The energy of protons is found to be in a good agreement with the diode voltage.
{"title":"\"Time-Resolved Measurement of Energy and Species of an Intense Pulsed Ion Beam\"","authors":"T. Matsuzawa, A. Takahashi, K. Masugata, M. Ito, Masao Matsui, K. Yatsui","doi":"10.1063/1.1138364","DOIUrl":"https://doi.org/10.1063/1.1138364","url":null,"abstract":"A time‐resolvable Thomson‐parabola spectrometer is developed employing a microchannel‐plate image intensifier, which acts as a high‐speed shutter (∼5 ns) by gating the applied voltage. Using such a spectrometer, we have achieved the measurement of temporal behavior of beam energy for various ion species of an intense pulsed ion beam extracted from a dual‐current‐feed magnetically insulated diode. The energy of protons is found to be in a good agreement with the diode voltage.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"73 1","pages":"88-101"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89000181","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 magnetosonic shock wave propagating obliquely to a magnetic field is studied by theory and simulation, with particular attention to the resonant ion acceleration (the vp×B acceleration) by the shock. Theoretical analysis based on a two‐fluid model shows that, in the laminar shock, the electric field strength in the direction normal to the wave is about (mi/me)1/2 times larger for the quasiperpendicular shock than that for the quasiparallel shock, which is a reflection of the fact that the width of the quasiperpendicular shock is much smaller than that of the quasiparallel shock. Time evolution of a totally self‐consistent magnetosonic shock wave is studied by using a 2 1/2 ‐dimensional fully relativistic, fully electromagnetic particle simulation with full ion and electron dynamics. Even the low Mach number shock wave can significantly accelerate some ions by the vp×B acceleration. The resonant ion acceleration occurs more strongly in the quasiperpendicular shock, because the magnitude of this accelerat...
{"title":"Resonant Ion Acceleration by Oblique Magnetosonic Shock Wave in a Collisionless Plasma","authors":"Y. Ohsawa","doi":"10.1063/1.865932","DOIUrl":"https://doi.org/10.1063/1.865932","url":null,"abstract":"A magnetosonic shock wave propagating obliquely to a magnetic field is studied by theory and simulation, with particular attention to the resonant ion acceleration (the vp×B acceleration) by the shock. Theoretical analysis based on a two‐fluid model shows that, in the laminar shock, the electric field strength in the direction normal to the wave is about (mi/me)1/2 times larger for the quasiperpendicular shock than that for the quasiparallel shock, which is a reflection of the fact that the width of the quasiperpendicular shock is much smaller than that of the quasiparallel shock. Time evolution of a totally self‐consistent magnetosonic shock wave is studied by using a 2 1/2 ‐dimensional fully relativistic, fully electromagnetic particle simulation with full ion and electron dynamics. Even the low Mach number shock wave can significantly accelerate some ions by the vp×B acceleration. The resonant ion acceleration occurs more strongly in the quasiperpendicular shock, because the magnitude of this accelerat...","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"124 1","pages":"1-39"},"PeriodicalIF":0.0,"publicationDate":"1985-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86436593","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}
Usually, it is very difficult to separate an electron current from H- or D- ion current under volume production, because both electrons and H- or D- ions are extracted from a discharge plasma in H2 or D2 gas. However, H- or D-ion current by volume production in the sheet plasma can be easily separated from electron current by using the weak magnetic field applied to the sheet plasma itself. Then, if the H- or D- ion current is compared with positive ion (mainly H+3 or D+3) current which is extracted by changing sign of the acceleration voltage from plus (for H- or D- ion) to minus, the H-or D- ion current can be confirmed more exactly.
{"title":"Measuring Method and Confirmation of H^-, D^- Ion Current by Sheet Plasma I","authors":"J. Uramoto","doi":"10.3131/JVSJ.28.742","DOIUrl":"https://doi.org/10.3131/JVSJ.28.742","url":null,"abstract":"Usually, it is very difficult to separate an electron current from H- or D- ion current under volume production, because both electrons and H- or D- ions are extracted from a discharge plasma in H2 or D2 gas. However, H- or D-ion current by volume production in the sheet plasma can be easily separated from electron current by using the weak magnetic field applied to the sheet plasma itself. Then, if the H- or D- ion current is compared with positive ion (mainly H+3 or D+3) current which is extracted by changing sign of the acceleration voltage from plus (for H- or D- ion) to minus, the H-or D- ion current can be confirmed more exactly.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"28 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"1985-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73709721","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}
Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a `saddle' point can be created in velocity space owing to v -3 dependence of the deflection rate and a positive slope or a `dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation.
{"title":"Collisional Relaxation of Electron Tail Distribution","authors":"M. Yamagiwa, M. Okamoto","doi":"10.1143/JPSJ.54.3763","DOIUrl":"https://doi.org/10.1143/JPSJ.54.3763","url":null,"abstract":"Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a `saddle' point can be created in velocity space owing to v -3 dependence of the deflection rate and a positive slope or a `dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"24 1","pages":"1-23"},"PeriodicalIF":0.0,"publicationDate":"1985-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75174767","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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