摘要:

A linear regression analysis of Joule energy deposition rates integrated over the northern hemisphere as a function of the standard auroral electrojet indices yields a correlation coefficient ofr= 0.7–0.9. Except for very disturbed times, when theAE(12) index tends to underestimate the electrojet current, the hemispherical Joule heating rate can be calculated by substituting 1 nT in theAEindex by approximately 0.3 GW. This scale factor is appreciably larger than those employed in earlier energy coupling studies. A higher‐scale factor is found for the regression between Joule heating caused by eastward current versusAUthan for that caused by the westward electrojet versusAL. This is consistent with typically lower ionospheric conductivity values in the eastward electrojet region which require higher electric fields and thus more Joule heating for a given eastward current orAUvalue than for the same intensity of the westward electro

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00383

年代:1984

数据来源: WILEY

摘要:

Nearly simultaneous data from the Chatanika radar, the TRIAD satellite, and the IMS Alaska meridian chain of magnetic and auroral observatories are utilized to examine the spatial relationship among auroras, field‐aligned currents, ionospheric electric fields, and conductivities in the westward electrojet in early morning hours. The westward electrojet is found to be dominated by one of two different quantities, depending on latitudinal locations in this local time sector. The poleward half of the electrojet is governed by a relatively intense southward electric field. On the other hand the Hall conductivity is the dominant factor in controlling the electrojet current in the equatorward half. The electrojet center appears to be located within the region of the upward field‐aligned current. Major auroral activity is present only in the equatorward half of the electrojet in which the upward field‐aligned current prevails, although it appears that the latitudinal variations of the conductivity and current intensity are not well related within that r

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00389

年代:1984

数据来源: WILEY

摘要:

Consideration of the force balance of the ring plasma generated by meteoroid impact in the rotating ionosphere of Saturn is extended to include the magnetic mirroring effect. It is found that there are modifications to the so‐called siphon flow limit derived for charged particles with zero magnetic moment if the ionospheric plasma has a thermal temperature exceeding a few electron volts. The nature of the force balance is such that, instead of a sharp division between complete loss and complete reabsorption, a transition zone of partial loss appears. If part of the ions near the rings are produced by ionization of the neutral atmosphere in the vicinity of the ring system (also generated by meteoroid impact vaporization), another theoretical limit dividing the upward flow from the equatorially confined motion is located near the observed boundary between the B ring and the C ring. This new limit is very sharp, as required to explain the B‐C ring boundary, which has not yet been explained by gravitational the

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00395

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00399

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00401

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00403

年代:1984

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JA089iA01p00404

年代:1984

数据来源: WILEY