Inertial magnetic reconnection effects on the electron dynamics in a three-dimensional configuration

Abstract. The simplest models of the electrostatic solitary waves observed by the Geotail spacecraft in the magnetosphere are developed proceeding from the concept of electron phase space holes. The technique to construct the models is based on an approximate quasi-one-dimensional description of the electron dynamics and three-dimensional analysis of the electrostatic structure of the localized wave perturbations. It is shown that the Vlasov-Poisson set of equations admits a wide diversity of model solutions of different geometry, including spatial configurations of the electrostatic potential similar to those revealed by Geotail and other spacecraft in space plasmas.

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Role of Z-pinches in magnetic reconnection in space plasmas

Journal of Plasma Physics ◽

10.1017/s0022377814000725 ◽

2014 ◽

Vol 81 (1) ◽

Cited By ~ 4

Author(s):

Vyacheslav Olshevsky ◽

Giovanni Lapenta ◽

Stefano Markidis ◽

Andrey Divin

Keyword(s):

Magnetic Reconnection ◽

Magnetic Energy ◽

Large Fraction ◽

Three Dimensional ◽

Space Plasmas ◽

Particle In Cell ◽

Cell Simulation ◽

Field Lines ◽

Three Dimensional Configuration

A widely accepted scenario of magnetic reconnection in collisionless space plasmas is the breakage of magnetic field lines in X-points. In laboratory, reconnection is commonly studied in pinches, current channels embedded into twisted magnetic fields. No model of magnetic reconnection in space plasmas considers both null-points and pinches as peers. We have performed a particle-in-cell simulation of magnetic reconnection in a three-dimensional configuration where null-points are present initially, and Z-pinches are formed during the simulation along the lines of spiral null-points. The non-spiral null-points are more stable than spiral ones, and no substantial energy dissipation is associated with them. On the contrary, turbulent magnetic reconnection in the pinches causes the magnetic energy to decay at a rate of ~1.5% per ion gyro period. Dissipation in similar structures is a likely scenario in space plasmas with large fraction of spiral null-points.

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Improvement on Permeability of Cyclic Peptide/Peptidomimetic: Backbone N-Methylation as A Useful Tool

Marine Drugs ◽

10.3390/md19060311 ◽

2021 ◽

Vol 19 (6) ◽

pp. 311

Author(s):

Yang Li ◽

Wang Li ◽

Zhengshuang Xu

Keyword(s):

Cyclic Peptides ◽

Cyclic Peptide ◽

Three Dimensional ◽

Conformational Space ◽

Cell Permeability ◽

Relative Importance ◽

Intrinsic Properties ◽

Surface Areas ◽

Synthetic Methodologies ◽

Three Dimensional Configuration

Peptides have a three-dimensional configuration that can adopt particular conformations for binding to proteins, which are well suited to interact with larger contact surface areas on target proteins. However, low cell permeability is a major challenge in the development of peptide-related drugs. In recent years, backbone N-methylation has been a useful tool for manipulating the permeability of cyclic peptides/peptidomimetics. Backbone N-methylation permits the adjustment of molecule’s conformational space. Several pathways are involved in the drug absorption pathway; the relative importance of each N-methylation to total permeation is likely to differ with intrinsic properties of cyclic peptide/peptidomimetic. Recent studies on the permeability of cyclic peptides/peptidomimetics using the backbone N-methylation strategy and synthetic methodologies will be presented in this review.

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