Helicity transport and dynamo sustainment for helical plasma states
Plasma states dominated by single helical modes are often observed in the Reverse Field Pinch (RFP) plasma confinement devices. In this paper the properties of these states are studied on the basis of a relaxation model that assumes the existence of several topological invariants related to the domi...
| Main Author: | |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2019-01-01
|
| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/ab4383 |
| _version_ | 1797750027219632128 |
|---|---|
| author | R Paccagnella |
| author_facet | R Paccagnella |
| author_sort | R Paccagnella |
| collection | DOAJ |
| description | Plasma states dominated by single helical modes are often observed in the Reverse Field Pinch (RFP) plasma confinement devices. In this paper the properties of these states are studied on the basis of a relaxation model that assumes the existence of several topological invariants related to the dominant mode. It is hypothesized that the value of the first invariant in this chain, is determined by the existence of a plasma dynamo mechanism that transport helicity. This hypothesis enables us to determine the steady state properties of the plasma equilibrium and some other interesting physical consequences. Further, by considering the properties of the transfer of helicity from the mesoscale (fluctuations) to the macroscale (equilibrium), through the dynamo field, a nonlinear dynamical model can be constructed, that evolves in time to a steady state with a non-vanishing dynamo field, when helicity is injected in the system, as in the case of the ohmic sustained RFP, while the dynamo oscillates initially, but is damped later in time, for vanishing helicity input. |
| first_indexed | 2024-03-12T16:27:52Z |
| format | Article |
| id | doaj.art-cdf61d6bf76a4dd596f84e6541bacd8b |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:27:52Z |
| publishDate | 2019-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-cdf61d6bf76a4dd596f84e6541bacd8b2023-08-08T15:40:34ZengIOP PublishingNew Journal of Physics1367-26302019-01-0121909304510.1088/1367-2630/ab4383Helicity transport and dynamo sustainment for helical plasma statesR Paccagnella0https://orcid.org/0000-0002-0522-7971Consorzio RFX, Corso Stati Uniti 4 , I-35127, Padova, Italy; ISTP-Consiglio Nazionale delle Ricerche, ItalyPlasma states dominated by single helical modes are often observed in the Reverse Field Pinch (RFP) plasma confinement devices. In this paper the properties of these states are studied on the basis of a relaxation model that assumes the existence of several topological invariants related to the dominant mode. It is hypothesized that the value of the first invariant in this chain, is determined by the existence of a plasma dynamo mechanism that transport helicity. This hypothesis enables us to determine the steady state properties of the plasma equilibrium and some other interesting physical consequences. Further, by considering the properties of the transfer of helicity from the mesoscale (fluctuations) to the macroscale (equilibrium), through the dynamo field, a nonlinear dynamical model can be constructed, that evolves in time to a steady state with a non-vanishing dynamo field, when helicity is injected in the system, as in the case of the ohmic sustained RFP, while the dynamo oscillates initially, but is damped later in time, for vanishing helicity input.https://doi.org/10.1088/1367-2630/ab4383reverse field pinchdynamorelaxationhelicityhelicity transport |
| spellingShingle | R Paccagnella Helicity transport and dynamo sustainment for helical plasma states New Journal of Physics reverse field pinch dynamo relaxation helicity helicity transport |
| title | Helicity transport and dynamo sustainment for helical plasma states |
| title_full | Helicity transport and dynamo sustainment for helical plasma states |
| title_fullStr | Helicity transport and dynamo sustainment for helical plasma states |
| title_full_unstemmed | Helicity transport and dynamo sustainment for helical plasma states |
| title_short | Helicity transport and dynamo sustainment for helical plasma states |
| title_sort | helicity transport and dynamo sustainment for helical plasma states |
| topic | reverse field pinch dynamo relaxation helicity helicity transport |
| url | https://doi.org/10.1088/1367-2630/ab4383 |
| work_keys_str_mv | AT rpaccagnella helicitytransportanddynamosustainmentforhelicalplasmastates |