THREE DIMENSIONAL STUDY ON PULSAR MAGNETOSPHERE WHICH CREATES ELECTRON-POSITRON PAIRS

产生电子-正电子对的脉冲星磁层的三维研究

• 批准号: 08454047
• 负责人: SHIBATA Shinpei
• 金额: $ 3.07万
• 依托单位: YAMAGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454047/
• 关键词: particle acceleration; QED (Quantum electrodynamics); magnetosphere; pulsar; X-ray; gamma-ray; special porpouse computer; plasma; 中性子星; 電子陽電子対; 数値シミュレーション

Mechanism of particle acceleration in the pulsar magnetosphere is mostly studied in the axisymmetric case because analysis in non-axisymmetric case, i.e., in the case that the magnetic axis is inclined to the rotation axis, is tremendously difficult. This project callenges to this non-aligned case. Note the real pulsar system is indeed non-aligned completely three dimensional system. Although we have to deal with large numerical calculation, we overcome this problem by using a special porpouse computer. The use of a special porpouse computer makes this project distinctive to other works.(1) In the first step, we analytically study the formation of the field-aligned electric field, which accelerate particles on the polar caps. There are two kind of magnetic field lines : the field lines curving toward the rotation axis and those curving away the rotation axis. It was proposed that acceleration takes place only on the 'toward field lines'. However, I showed that particle acceleration takes place regardless of field line curvature if the current density is larger than a critical value. This acceleration is shown to be strong enough to cause electron-positron pair creation cascade. (Shibata 1997)(2) In the non-aligned case, there is an effect of the displacement current on the field structure. The convection current also contribute to the field structure. Including the both effects, we calculate the field structure of the perpendicular rotator in the force-free case. (Mestel and Shibata, 1998 in preparation)(3) I developed a particle-code for the three-dimensional magnetospheric model on the special porpouse computer Harp-3 (2.2Gflops). Hape-3 was original made for gravitationary interacting particles, but we use it for Coulomb interaction. This code will be used to study a electrosphere in which pair creation takes place. This is an important step for the future calculation for particle simulation of the magnetosphere with pair discharge.

脉冲星磁层中粒子加速机制的研究主要是在轴对称情况下进行的，因为非轴对称情况下的分析，即，在磁轴倾斜于旋转轴的情况下，是非常困难的。这一项目符合这一不结盟的情况。注意，真实的脉冲星系统实际上是完全非对准的三维系统。虽然我们必须处理大量的数值计算，我们克服了这个问题，通过使用一个特殊的porpouse计算机。一个特殊的porpouse计算机的使用使这个项目与众不同的其他作品。(1)在第一步中，我们分析研究了场向电场的形成，它加速了极冠上的粒子。磁力线有两种：向旋转轴弯曲的磁力线和远离旋转轴弯曲的磁力线。有人提出，加速度只发生在“向磁力线”。然而，我表明，如果电流密度大于一个临界值，粒子加速发生场线曲率无关。这种加速被证明是强大到足以导致电子-正电子对创建级联。（柴田1997）（2）在非对准的情况下，存在位移电流对场结构的影响。对流对场结构也有贡献。在考虑这两种效应的情况下，我们计算了垂直旋光体在无力情况下的场结构。（Mestel and柴田，1998 in preparation）（3）在Harp-3（2.2Gflops）上开发了三维磁层模型的粒子程序。Hape-3最初是为引力相互作用粒子制造的，但我们用它来研究库仑相互作用。这段代码将被用来研究一个电层，在这个电层中，电子对的产生发生。这为进一步开展磁层对放电粒子模拟计算工作迈出了重要的一步。

项目成果

S.Shibata et al.: "X-ray Nebula around the Gammaray Pulsar PSR 1055-52" Astrophysical Journal. 483. 843-848 (1997)

S.Shibata 等人：“伽马射线脉冲星 PSR 1055-52 周围的 X 射线星云”天体物理学杂志。

N.Shibazaki et al.: "Neutron Stars and Pulsars". Universal Academy Press Tokyo, Japan, 600 (1998)

N.Shibazaki 等人：“中子星和脉冲星”。

M.Takahashi and S.Shibata: "Trans-fast MHD winds in a Pulsar Magnetosphere" Publication of Astron.Soc.of Japan. (in press).

M.Takahashi 和 S.Shibata：“脉冲星磁层中的超快 MHD 风”由 Astron.Soc.of 日本出版。

S.Shibata他11名: "X-ray Nebnla around the Gamma-ray Pulsar PSR1055-52" The Astropysical Journal. (印刷中). (1997)

S. Shibata 和其他 11 人：“伽马射线脉冲星 PSR1055-52 周围的 X 射线 Nebnla”，天体物理学杂志（1997 年）。

S., Shibata 他: "X-ray Nebula around the Gamma-ray Pulsar PSR1055-52" Astrophysical Journal. 483. 843-848 (1997)

S., Shibata 等人：“伽马射线脉冲星 PSR1055-52 周围的 X 射线星云”《天体物理学杂志》483. 843-848 (1997)。