The electrical conductivity of the ionosphere: A review

Chapman, Sydney

doi:10.1007/bf02746310

Cited by 216 publications

(63 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The theory appears to be best applicable in the polar regions where the magnetic field is vertical and therefore we need not be concerned in the first instance with gradients of density and conductivity in the direction of E'. Figure 1 shows a.-I and ~-I plotted as functions of height using Chapman's (1956) model atmosphere for conductivity (his model h) and also in an atmosphere in which the electron density is 10 times that of Chapman's (to simulate disturbed conditions in the auroral regions). For this calculation densities used are those of the Rocket Panel (cf.…”

Section: Theory (A) Fields In a Uniform Ionized Gasmentioning

confidence: 99%

“…for the driving electric field of geomagnetic disturbance in a particular instance. He assumed an enhanced average conductivity 20 times that of Fejer whose model is comparable to Chapman's (1956) model. Evidence in favour of enhanced electron density (of order 10 6 cm-3 ) over wide regions in the auroral E-region may be found in the work of Heppner, Byrne, and Belon (1952) and Knecht (1956), and in auroral forms in the work of Seaton (1954) and Ohmolt (1954,1961).…”

Section: (C) Winds In a Disturbed Ionospherementioning

confidence: 99%

See 1 more Smart Citation

Joule Heating of the Upper Atmosphere

Cole¹

1962

Aust. J. Phys.

216

103

View full text Add to dashboard Cite

SumnnaryThe joule heating and motion of uniform ionized gas is discussed, on the assumption that uniform electric and mechanical force fields are orthogonal to the (homogeneous) magnetic field. Application to the ionosphere during geomagnetic disturbance reveals (i) Joule heating at a rate of order 10-5 erg cm-3 sec-1 in the region 100 to 200 km altitude at the auroral zone is common during geomagnetic disturbance.(ii) Scale heights and temperatures at altitudes above about 100 km increase with geomagnetic disturbance. (iii) The energy of the process causing geomagnetic disturbance is in general not measureable by the energy of geomagnetic disturbance. (iv) A horizontal gradient of pressure of size 10-10 dyne cm-3 may be maintained at heights above 150 km in the auroral zone during geomagnetic disturbance. (v) Wind speeds in the polar ionosphere increase with geomagnetic disturbance.

show abstract

Section: Theory (A) Fields In a Uniform Ionized Gasmentioning

confidence: 99%

Section: (C) Winds In a Disturbed Ionospherementioning

confidence: 99%

Joule Heating of the Upper Atmosphere

Cole¹

1962

Aust. J. Phys.

216

103

View full text Add to dashboard Cite

show abstract

“…With respect to the comparison between the conductivities ratio we attribute the difference to the collision rates used into the present model. We have used the expression of ion-neutron collision frequency given by Chapman (1956), and an update of this equation is needed.…”

Section: Resultsmentioning

confidence: 99%

A conductivity model for the Brazilian equatorial e-region: initial results

Denardini¹

2007

Rev. Bras. Geof.

View full text Add to dashboard Cite

ABSTRACT. This paper presents results from a new model of field-line-integrated ionospheric conductivity for the Brazilian equatorial region. It was developed aiming to calculate zonal electric fields at E-region heights in the equatorial region. The present model is based on a constant neutral atmosphere model and on an empirical electron densities model (which also gives the ion composition) adjusted by E-region electron density measured by digisonde. It is also based on a geomagnetic field model that we approximate with a dipole which is not located at the centre of the Earth due to the large magnetic declination angle in the Brazilian sector. We have also considered the eccentric dipole having an inclination of 20 • with respect to the Earth rotation axis. The conductivities are calculated for the year 2002 and the results from the present model are compared to those obtained from the conductivity model of the Kyoto University.Keywords: ionosphere, aeronomy, local conductivity, field aligned conductivity, model. RESUMO.Este trabalho apresenta os primeiros resultados de um novo modelo para o cálculo de condutividades integradas ao longo das linhas de campo magnético, válido na região E ionosférica do setor brasileiro. Este modelo foi desenvolvido com o objetivo de se calcular os campos elétricos zonais da região E da ionosfera equatorial. Este modeloé baseado em um modelo de atmosfera neutra constante e em um modelo empírico de densidades eletrônicas (o qual também fornece a composição iônica) corrigido pela densidade eletrônica da região E medida por digissondas. Devido a grande declinação magnética no setor brasileiro o modelo geomagnético foi aproximado pelo modelo do dipolo não centrado com respeito ao centro da Terra. Também consideramos que o dipolo excêntrico possui uma inclinação de 20 • com respeito ao eixo de rotação da Terra. As condutividades foram calculadas para o ano de 2002 e os valores resultantes do presente modelo foram comparados com as condutividades obtidas pelo modelo de condutividade da Universidade de Kyoto -Japão.Palavras-chave: ionosfera, aeronomia, condutividade local, condutividade alinhada ao campo magnético, modelo.

show abstract

“…There is little ionization at heights below 900 km, so the conducting layer is roughly 150 km thick (i.e., approximately from 900 to 1050 km), with an average electron density of about 5 Â 10 9 m À3 . Using the standard theory (Chapman, 1956;Rishbeth and Garriott, 1969), a rough estimate gives the heightintegrated conductivity (Pedersen and Hall components) as s s sdhH1 mho, similar to that of the Earth's ionosphere. With winds of order 60 m s À1 , the total current might approach that in the Earth's ionosphere, with a possible component due to the Saturn tide (Section 8).…”

Section: Electric ®Elds and Currentsmentioning

confidence: 99%

Dynamics of Titan’s thermosphere

Rishbeth

Yelle

Mendillo

2000

Planetary and Space Science

View full text Add to dashboard Cite

We estimate the wind speeds in Titan's thermosphere by considering the various terms of the wind equation, without actually solving it, with a view to anticipating what might be observed by the Cassini spacecraft in 2004. The winds, which are driven by horizontal pressure gradients produced by solar heating, are controlled in the Earth's thermosphere by ion-drag and coriolis force, but in Titan's thermosphere they are mainly controlled by the nonlinear advection and curvature forces. Assuming a day± night temperature di erence of 20 K, we ®nd that Titan's thermospheric wind speed is typically 60 m s À1 . In contrast, the Earth's thermospheric winds, of order 50 m s À1 , do not equalize day and night temperatures. We speculate on other factors, such as the electrodynamics of Titan's thermosphere and the tides due to Saturn. #

show abstract

The electrical conductivity of the ionosphere: A review

Cited by 216 publications

References 17 publications

Joule Heating of the Upper Atmosphere

Joule Heating of the Upper Atmosphere

A conductivity model for the Brazilian equatorial e-region: initial results

Dynamics of Titan’s thermosphere

Contact Info

Product

Resources

About