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Abstract The inductive component of the magnetospheric electric field, which is associated with the temporal change of magnetic field, provides an additional means of local plasma energization and transport in addition to the electrostatic counterpart. This study examines the detailed response of the inner magnetosphere to inductive electric fields and the associated electric‐driven convection corresponding to different solar wind conditions. A novel modeling capability is employed to self‐consistently simulate the electromagnetic and plasma environment of the entire magnetospheric cavity. The explicit separation of the electric field by source (inductive vs. electrostatic) and subsequent implementation of inductive effects in the ring current model allow us to investigate, for the first time, the effect of the inductive electric field on the kinetics and evolution of the ring current system. The simulation results presented in this study demonstrate that the inductive component of the electric field is capable of providing an additional source for long‐lasting plasma drifts, which in turn significantly alter the trajectories of both thermal and energetic particles. Such changes in the plasma drift, which arise due to the inductive electric fields, further reshape the storm‐time ring current morphology and alter the degree of the ring current asymmetry, as well as the timing and the peak of the ion pressure. The total ion energy is increasing at a faster rate than the supply of energetic ions to the ring current, suggesting that the inductive electric field provides effective and accumulative local energization for the trapped ring current population without confining additional particles.
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Electric fields imbue enzyme reactivity by aligning active site fragment orbitals
It is broadly recognized that intramolecular electric fields, produced by the protein scaffold and acting on the active site, facilitate enzymatic catalysis. This field effect can be described by several theoretical models, each of which is intuitive to varying degrees. In this contribution, we show that a fundamental effect of electric fields is to generate electrostatic potentials that facilitate the energetic alignment of reactant frontier orbitals. We apply this model to demystify the impact of electric fields on high-valent iron–oxo heme proteins: catalases, peroxidases, and peroxygenases/monooxygenases. Specifically, we show that this model easily accounts for the observed field-induced changes to the spin distribution within peroxidase active sites and explains the transition between epoxidation and hydroxylation pathways seen in Cytochrome P450 active site models. Thus, for the intuitive interpretation of the chemical effect of the field, the strategy involves analyzing the response of the orbitals of active site fragments, and their energetic alignment. We note that the energy difference between fragment orbitals involved in charge redistribution acts as a measure for the chemical hardness/softness of the reactive complex. This measure, and its sensitivity to electric fields, offers a single parameter model from which to quantitatively assess the effects of electric fields on reactivity and selectivity. Thus, the model provides an additional perspective to describe electrostatic preorganization and offers ways for its manipulation.
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- Award ID(s):
- 2203366
- PAR ID:
- 10651422
- Publisher / Repository:
- National Academy of Sciences
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 121
- Issue:
- 44
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1073/pnas.2411976121
