Search results for " magnetic reconnection"

Reconnection nanojets in the solar corona

2020

P.A. acknowledges STFC support from grant numbers ST/R004285/2 and ST/T000384/1 and support from the International Space Science Institute, Bern, Switzerland to the International Teams on ‘Implications for coronal heating and magnetic fields from coronal rain observations and modeling’ and ‘Observed Multi-Scale Variability of Coronal Loops as a Probe of Coronal Heating’. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 647214). P.T. was also supported by contracts 8100002705 and SP02H1701R from Lockheed-Martin to the Smithsonian Astrophysical Observatory (SAO), and NASA c…

Three-dimensional features in burning plasmas

2019

A next major step in the research toward magnetic fusion energy production is to carry out experimental campaigns exploring regimes with relevant amount of fusion power. So far, the theoretical knowledge of the path toward a fusion burning plasma has been acquired mainly by performing numerical studies in 0 or 1-1.5 dimensions. Due to the marked anisotropy of magnetically confined plasmas, however, three-dimensional effects might play a role. In particular, the drastic change in magnetic topology associated with reconnecting modes on selected rational magnetic surfaces [1] may decrease the thermal electron conductivity parallel to the magnetic field lines, with a consequent impact on the el…

Fusion Burning in Magnetically Confined Toroidal Plasmas

The thermonuclear instability in a toroidal fusion burning plasma [1] is shown to manifest itself as a driving factor of modes that are radially localized around closed field lines on rational magnetic surfaces. The radial profile of the electron temperature perturbations can be of two parities: even and odd. In the first case the effective longitudinal thermal conductivity can be reduced by the effects of modes involving magnetic reconnection that have a radial transverse reconnected field with a odd (radial) profile. In the second case magnetic reconnection is shown to have a stronger effect and is characterized by reconnected transverse fields that have an even radial profile. A class of…

Thermal Energy Density Driven Magnetic Reconnection

Magnetic reconnection is usually associated with conversion of magnetic energy into particle acceleration or thermal energy. However, a specific reconnection process driven by plasma pressure gradients was identified in Ref.[1] with a consistent theory of (non-ideal) MHD m0=1 modes in well confined plasmas. This process, based on an Ohm's law contribution to the electron balance equations, remains the basis for the explanation of the observed sawtooth oscillations of the central plasma pressure and for the inferred magnetic field structures due to fishbone oscillations associated with injected high energy particle populations. A novel process [2] expected to have a wide range of application…

Cyclical generation of reconnected magnetic fields by electron pressure gra-dients

2021

The theoretical basis for the cyclical generation of macroscopic reconnected magnetic fields in low collisionality plasma regimes is formulated. The relevant process is sustained by the “thermal” energy of the electron population.In particular, an oscillatory mode propagating along and across a confining magnetic field is identified that involves the magnetic reconnection region where the ratio of the longitudinal to transverse electron thermal conductivity is relatively large. A periodic exchange of reconnected magnetic field conductivity energy with electron thermal energy is sustained within a region that remains significant even when the magnetic field configuration from which the mode …