Coherent radio emission in pulsars is excited due to instabilities in a relativistically streaming non-stationary plasma flow, which is generated from sparking discharges in the inner acceleration region (IAR) near the stellar surface. A number of detailed works have shown the IAR to be a partially screened gap (PSG) dominated by non-dipolar magnetic fields with continuous outflow of ions from the surface. The phenomenon of subpulse drifting is expected to originate due to variable $\mathbf{E}\times\mathbf{B}$ drift of the sparks in PSG, where the sparks lag behind corotation velocity of the pulsar. Detailed observations show a wide variety of subpulse drifting behaviour where subpulses in different components of the profile have different phase trajectories. But the drifting periodicity is seen to be constant, within measurement errors, across all components of the profile. Using the concept of sparks lagging behind corotation speed in PSG as well as the different orientations of the surface non-dipolar magnetic fields we have simulated the expected single pulse behaviour in a representative sample of pulsars. Our results show that the different types of drifting phase behaviour can be reproduced using these simple assumptions of spark dynamics in a non-dipolar IAR.

中文翻译：

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内加速区火花运动机制研究脉冲星亚脉冲漂移

脉冲星中的相干射电发射是由于相对论流动的非平稳等离子体流的不稳定性而被激发的，该等离子体流是由恒星表面附近的内部加速区 (IAR) 中的火花放电产生的。许多详细的工作表明 IAR 是一个部分屏蔽间隙 (PSG)，由非偶极磁场主导，离子从表面连续流出。亚脉冲漂移现象预计源于PSG中火花的变量$\mathbf{E}\times\mathbf{B}$漂移，其中火花滞后于脉冲星的共转速度。详细的观察显示了各种各样的子脉冲漂移行为，其中轮廓的不同分量中的子脉冲具有不同的相位轨迹。但是漂移周期被认为是恒定的，在测量误差范围内，跨配置文件的所有组件。使用 PSG 中火花滞后于共转速度的概念以及表面非偶极磁场的不同方向，我们模拟了脉冲星代表性样本中预期的单脉冲行为。我们的结果表明，使用非偶极 IAR 中火花动力学的这些简单假设，可以重现不同类型的漂移相行为。