Nondipole electron momentum offset as a probe of correlated three-electron ionization in strongly driven atoms
Nondipole electron momentum offset as a probe of correlated three-electron ionization in strongly driven atoms
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DOI：
10.1103/physreva.108.043111
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发表时间：
2022-10
影响因子：
2.9
通讯作者：
G. P. Katsoulis;M. Peters;A. Emmanouilidou
中科院分区：
文献类型：
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作者：
G. P. Katsoulis;M. Peters;A. Emmanouilidou
我们采用最近开发的三维半经典模型，以确定在三重电离的Ne驱动的红外激光脉冲的强度，电子-电子相关占上风的非偶极效应。该模型充分考虑了每个电子与核心的库仑相互作用，并通过采用有效库仑势来描述束缚电子之间的相互作用（ECBB）来避免人工自电离。使用ECBB模型，我们确定了一个突出的签名的非偶极子效应。即，最终电子动量的平均和的沿光传播方向的分量沿着是大的且正的。也就是说，我们确定了一个积极的动量偏移，在偶极子近似缺席。我们发现，这种积极的动量抵消主要源于由于磁场的动量变化。为了进一步理解这种动量变化，我们还建立了一个简单的模型，用于描述电子在电磁场中的运动。这个简单的模型只把库仑力的作用解释为电子在碰撞过程中动量的急剧变化。我们表明，由于磁场的动量变化与急剧变化的动量在碰撞过程中的碰撞电子以及碰撞和束缚电子的碰撞时间。因此，我们证明，最终的电子动量偏移探针的强度的一个电离，因此在多电子电离的相关程度。
We employ a recently developed three-dimensional semiclassical model to identify nondipole effects in triple ionization of Ne driven by infrared laser pulses at intensities where electron-electron correlation prevails. This model fully accounts for the Coulomb interaction of each electron with the core and avoids artificial autoionization by employing effective Coulomb potentials to describe the interaction between bound electrons (ECBB). Using the ECBB model, we identify a prominent signature of nondipole effects. Namely, the component along the direction of light propagation of the average sum of the final electron momenta is large and positive. That is, we identify a positive momentum offset, absent in the dipole approximation. We find that this positive momentum offset stems mostly from the momentum change due to the magnetic field. To further understand this momentum change, we also develop a simple model for the motion of an electron inside an electromagnetic field. This simple model accounts for the effect of the Coulomb forces only as a sharp change in the momentum of the electron during recollision. We show that the momentum change due to the magnetic field is related with the sharp change in momentum during recollision for the recolliding electron as well as with the time of recollision for both the recolliding and bound electrons. Hence, we demonstrate that the final electron momentum offset probes the strength of a recollision and hence the degree of correlation in multielectron ionization.