dor_id: 4132699

506.#.#.a: Público

590.#.#.d: Los artículos enviados a la revista "Geofísica Internacional", se juzgan por medio de un proceso de revisión por pares

510.0.#.a: Consejo Nacional de Ciencia y Tecnología (CONACyT); Scientific Electronic Library Online (SciELO); SCOPUS, Dialnet, Directory of Open Access Journals (DOAJ); Geobase

561.#.#.u: https://www.geofisica.unam.mx/

650.#.4.x: Físico Matemáticas y Ciencias de la Tierra

336.#.#.b: article

336.#.#.3: Artículo de Investigación

336.#.#.a: Artículo

351.#.#.6: http://revistagi.geofisica.unam.mx/index.php/RGI

351.#.#.b: Geofísica Internacional

351.#.#.a: Artículos

harvesting_group: RevistasUNAM

270.1.#.p: Revistas UNAM. Dirección General de Publicaciones y Fomento Editorial, UNAM en revistas@unam.mx

590.#.#.c: Open Journal Systems (OJS)

270.#.#.d: MX

270.1.#.d: México

590.#.#.b: Concentrador

883.#.#.u: https://revistas.unam.mx/catalogo/

883.#.#.a: Revistas UNAM

590.#.#.a: Coordinación de Difusión Cultural

883.#.#.1: https://www.publicaciones.unam.mx/

883.#.#.q: Dirección General de Publicaciones y Fomento Editorial

850.#.#.a: Universidad Nacional Autónoma de México

856.4.0.u: http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1227/1201

100.1.#.a: Falthammar, C. G.

524.#.#.a: Falthammar, C. G. (1991). Physics of the Aurora. Geofísica Internacional; Vol. 30 Núm. 4: Octubre 1, 1991; 197-211. Recuperado de https://repositorio.unam.mx/contenidos/4132699

245.1.0.a: Physics of the Aurora

502.#.#.c: Universidad Nacional Autónoma de México

561.1.#.a: Instituto de Geofísica, UNAM

264.#.0.c: 1991

264.#.1.c: 1991-10-01

653.#.#.a: Campos eléctricos alineados al campo magnético; Aurora; Aceleración de partículas; Magnetic-field aligned electic fields; Aurora; Particle acceleration

506.1.#.a: La titularidad de los derechos patrimoniales de esta obra pertenece a las instituciones editoras. Su uso se rige por una licencia Creative Commons BY-NC-ND 4.0 Internacional, https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode.es, para un uso diferente consultar al responsable jurídico del repositorio por medio del correo electrónico revistagi@igeofisica.unam.mx

884.#.#.k: http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/1227

001.#.#.#: 063.oai:revistagi.geofisica.unam.mx:article/1227

041.#.7.h: spa

520.3.#.a: The aurora, fascinating by its beauty and its multitude of forms, has turned out to be even more fascinating in terms of the physics to be learned from scientific study of it. In situ observations of the aurora and related phenomena have brought to light plasma physical processes, whose existence has a profound impact on our concept of space around us. Most of these processes are related to the auroral acceleration process. Whereas it has long been known that the aurora is caused by electrons of a few keY energy impinging on the upper atmosphere, the way in which these electrons gain their energy has been a crucial as well as controversial issue. There is now almost universal agreement that magnetic-field aligned electric fields play a key role, in confirmation of a prediction by Hannes Alfven more than three decades ago. Three main mechanisms that make such fields possible have been recognized. Probably all of them operate in the auroral acceleration region, but their relative roles are still to be determined. It has also become clear that there is an intric;ate interplay between these fields and various forms of wave-particle interactions involving time-dependent electric fields over a wide range of frequencies. Magnetic-field aligned electric fields have important consequences for the behaviour of a plasma, not only in terms of its capability to energize charged particles but also for the dynamics of the plasma itself, e.g. by violation of the "frozen field condition". Therefore the understanding of such fields also forms an important basis for understanding cosmical plasmas in general. The same forces that hurl the auroral electrons downwards also expel positive ions upwards into the magnetosphere. This expulsion can be so copious that occasionally large parts of the magnetosphere are dominated by oxygen plasma from the Earth"s own ionosphere, rather than by hydrogen plasma from the solar wind. For reasons that we are only beginning to understand, the expulsion is highly selective. In other words, it constitutes an efficient chemical separation mechanism, whose very existence was completely unexpected until recently. As similar separation mechanisms may operate in other astrophysical plasmas, the significance of this discovery could be far-reaching. It has been emphasized by Alfven that the lessons learned in accessible regions of the space plasma necessitate a change of paradigm, which affects all of astrophysics, cosmology and cosmogony. Most of these lessons have c(,)me from study of problems related to the .aurora, and there may still be more to come.

773.1.#.t: Geofísica Internacional; Vol. 30 Núm. 4: Octubre 1, 1991; 197-211

773.1.#.o: http://revistagi.geofisica.unam.mx/index.php/RGI

022.#.#.a: ISSN-L: 2954-436X; ISSN impreso: 0016-7169

310.#.#.a: Trimestral

300.#.#.a: Páginas: 197-211

264.#.1.b: Instituto de Geofísica, UNAM

doi: https://doi.org/10.22201/igeof.00167169p.1991.30.4.1227

handle: 0ba8ec6a448ce164

harvesting_date: 2023-06-20 16:00:00.0

856.#.0.q: application/pdf

file_creation_date: 2022-07-05 10:51:18.0

file_modification_date: 2022-07-24 01:27:15.0

file_creator: C. G. Falthammar

file_name: 0170157f9bf8585f7e77cf9fb6db89887f64aa980fcc6a5945ce16a0d22b34ae.pdf

file_pages_number: 16

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245.1.0.b: Physics of the Aurora

last_modified: 2023-06-20 16:00:00

license_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode.es

license_type: by-nc-nd

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Artículo

Physics of the Aurora

Falthammar, C. G.

Instituto de Geofísica, UNAM, publicado en Geofísica Internacional, y cosechado de Revistas UNAM

Licencia de uso

Procedencia del contenido

Entidad o dependencia
Instituto de Geofísica, UNAM
Revista
Repositorio
Contacto
Revistas UNAM. Dirección General de Publicaciones y Fomento Editorial, UNAM en revistas@unam.mx

Cita

Falthammar, C. G. (1991). Physics of the Aurora. Geofísica Internacional; Vol. 30 Núm. 4: Octubre 1, 1991; 197-211. Recuperado de https://repositorio.unam.mx/contenidos/4132699

Descripción del recurso

Autor(es)
Falthammar, C. G.
Tipo
Artículo de Investigación
Área del conocimiento
Físico Matemáticas y Ciencias de la Tierra
Título
Physics of the Aurora
Fecha
1991-10-01
Resumen
The aurora, fascinating by its beauty and its multitude of forms, has turned out to be even more fascinating in terms of the physics to be learned from scientific study of it. In situ observations of the aurora and related phenomena have brought to light plasma physical processes, whose existence has a profound impact on our concept of space around us. Most of these processes are related to the auroral acceleration process. Whereas it has long been known that the aurora is caused by electrons of a few keY energy impinging on the upper atmosphere, the way in which these electrons gain their energy has been a crucial as well as controversial issue. There is now almost universal agreement that magnetic-field aligned electric fields play a key role, in confirmation of a prediction by Hannes Alfven more than three decades ago. Three main mechanisms that make such fields possible have been recognized. Probably all of them operate in the auroral acceleration region, but their relative roles are still to be determined. It has also become clear that there is an intric;ate interplay between these fields and various forms of wave-particle interactions involving time-dependent electric fields over a wide range of frequencies. Magnetic-field aligned electric fields have important consequences for the behaviour of a plasma, not only in terms of its capability to energize charged particles but also for the dynamics of the plasma itself, e.g. by violation of the "frozen field condition". Therefore the understanding of such fields also forms an important basis for understanding cosmical plasmas in general. The same forces that hurl the auroral electrons downwards also expel positive ions upwards into the magnetosphere. This expulsion can be so copious that occasionally large parts of the magnetosphere are dominated by oxygen plasma from the Earth"s own ionosphere, rather than by hydrogen plasma from the solar wind. For reasons that we are only beginning to understand, the expulsion is highly selective. In other words, it constitutes an efficient chemical separation mechanism, whose very existence was completely unexpected until recently. As similar separation mechanisms may operate in other astrophysical plasmas, the significance of this discovery could be far-reaching. It has been emphasized by Alfven that the lessons learned in accessible regions of the space plasma necessitate a change of paradigm, which affects all of astrophysics, cosmology and cosmogony. Most of these lessons have c(,)me from study of problems related to the .aurora, and there may still be more to come.
Tema
Campos eléctricos alineados al campo magnético; Aurora; Aceleración de partículas; Magnetic-field aligned electic fields; Aurora; Particle acceleration
Idioma
spa
ISSN
ISSN-L: 2954-436X; ISSN impreso: 0016-7169

Enlaces