摘要:

The theory of resonant ion acceleration which has been recently developed is compared quantitatively with the acceleration of energetic ions by a quasiperpendicular shock observed by Voyager 2 at a distance of ∼ 1.9 AU from the Sun. The theory explains many important features of the experimental result

ISSN:0094-8276    

DOI:10.1029/GL014i002p00095

年代:1987

数据来源: WILEY

摘要:

ISEE observations have shown trapped ion distributions in the magnetosphere along with streaming ion distributions in the magnetosheath. The more energetic ion beams are found to exist further away from the magnetopause than lower‐energy ion beams. In order to understand these properties of the data, we have taken a simple two‐dimensional reconnection model which contains a neutral line and an azimuthal electric field and compared its predictions with the experimental data of September 8, 1978. Our model explains trapped particles in the magnetosphere due to non‐adiabatic mirroring in the magnetosheath and streaming ions in the magnetosheath due to energization at the magnetopause. The model also shows the higher‐energy ions extending further into the magnetosheath, away from the magnetopause than the lower‐energy ions. This suggests the ion data of September 8, 1978 are consistent with a reconnection

ISSN:0094-8276    

DOI:10.1029/GL014i002p00099

年代:1987

数据来源: WILEY

摘要:

It is numerically shown that the fast reconnection in a closed system gives rise to strong heating of a magnetic loop. The supersonic plasma jet resulting downstream of the slow shocks collides with the loop and is effectively converted into plasma heating by the fast shock standing in front of the loop. The heated plasma (by a factor of more than 10) is accumulated in the loop head and is finally distributed along the loop boundary.

ISSN:0094-8276    

DOI:10.1029/GL014i002p00103

年代:1987

数据来源: WILEY

摘要:

The turbulence produced by lower hybrid waves, during interaction of solar wind with the cometary pick‐up ions, leads to stochastic acceleration of these ions. The resulting energies of the cometary ions, calculated on the assumption that the entire turbulent electric field is used up for accelerating particles, are much larger compared to the recently observed energies of water‐group ions in the vicinity of comets Halley as well as Giacobini‐Zinner. Accounting for the fact that only a fraction of the field would lead to acceleration and the rest to heating, lower hybrid waves seem to be a potential source for the observed energetic cometary

ISSN:0094-8276    

DOI:10.1029/GL014i002p00107

年代:1987

数据来源: WILEY

摘要:

Recent observations from the EISCAT incoherent scatter radar have revealed bursts of poleward ion flow in the dayside auroral ionosphere which are consistent with the ionospheric signature of flux transfer events at the magnetopause. These bursts frequently contain ion drifts which exceed the neutral thermal speed and, because the neutral thermospheric wind is incapable of responding sufficiently rapidly, toroidal, non‐Maxwellian ion velocity distributions are expected. The EISCAT observations are made with high time resolution (15 seconds) and at a large angle to the geomagnetic field (73.5°), allowing the non‐Maxwellian nature of the distribution to be observed remotely for the first time. The observed features are also strongly suggestive of a toroidal distribution: characteristic spectral shape, increased scattered power (both consistent with reduced Landau damping and enhanced electric field fluctuations) and excessively high line‐of‐sight ion temperatures deduced if a Maxwellian distribution is assumed. These remote sensing observations allow the evolution of the distributions to be observed. They are found to be non‐Maxwellian whenever the ion drift exceeds the neutral thermal speed, indicating that such distributions can exist over the time scale of the flow burst events (severa

ISSN:0094-8276    

DOI:10.1029/GL014i002p00111

年代:1987

数据来源: WILEY

摘要:

Simultaneous observations of pulsating auroras were carried out in September, 1984, using all‐sky TV cameras at a geomagnetically conjugate pair of stations: Syowa Station in Antarctica and Husafell in Iceland. From the data obtained at the two places on 26 September, the following characteristics are found: Spatial configuration of pulsating auroras is very similar in the conjugate regions. In this particular event each pulsating aurora has its counterpart with topologically the same shape in the other hemisphere. However, the timing of the appearance or fade‐out of the pulsating auroras depends on the type of aurora. That is, the patchy type of aurora appears nearly simultaneously in both hemispheres, but the expansion type of pulsating aurora, extending from an aurora with much slower variations, is not synchronously observed and often appears almost out of phase between the conjugate regi

ISSN:0094-8276    

DOI:10.1029/GL014i002p00115

年代:1987

数据来源: WILEY

摘要:

The bandwidths of the discrete spectral components of the auroral kilometric radiation can sometimes be as narrow as 5 Hz. Since this would imply an apparent source thickness of substantially less than the wavelength, it is inconsistent with the previous explanation for such discrete components based simply upon vertical localization of a cyclotron source. Instead, such narrow bandwidths can only be explained by radio lasing.

ISSN:0094-8276    

DOI:10.1029/GL014i002p00119

年代:1987

数据来源: WILEY

摘要:

OH concentrations in ambient air outside Ford Laboratory were measured in the months of July and August 1986 using the fluorescence technique at low pressures. The peak OH concentration was observed to be about 3 × 106molecules/cm³; the daytime average OH concentration was found to be in the range of middle 105molecules/cm³, and the nighttime average below the detection limit of 0.9 × 105molecules/cm³. It is demonstrated that use of moving average may create the appearance of oscillatory behavior in the diurnal variations of the deduced OH concentra

ISSN:0094-8276    

DOI:10.1029/GL014i002p00123

年代:1987

数据来源: WILEY

摘要:

It has been demonstrated that the reaction between gaseous chlorine nitrate and water on room temperature liquid sulfuric acid (95.6%) surfaces yields hypochlorous acid in the gas phase. First‐order loss rate constants for chlorine nitrate (equivalent to a value of the sticking coefficient γ = 3.2 × 10−4) have been determined. This value is five orders‐of‐magnitude greater than reported values on similar areas of more inert surfaces. Application of results of this type to stratospheric models must await ongoing studies at lower tem

ISSN:0094-8276    

DOI:10.1029/GL014i002p00127

年代:1987

数据来源: WILEY

摘要:

Two independent lines of evidence suggest that the hydrogen sulfides (H2S, SH−, S2−) are present in open surface seawater at pico to nanomolar levels. 1) Such concentrations are calculated for a chemical steady state involving carbonyl sulfide hydrolysis as source, followed by oxidative removal. 2) Although it is not yet certain that measurements of gaseous H2S over the open ocean are reliable, they require aqueous sulfide concentrations in this range in order to support sea‐to‐air flux. If pico to nanomolar of the hydrogen sulfides are included in standard equilibrium models of seawater complexation chemistry, several trace metals speciate predominantly as sulfide complexes and are supersaturated with respect to their solid sulfides. This supersaturation argues for solubilization of the metals through other unexpected complexes, perhaps involving reduced sulfur ligands associated with dissolved organics, or even intermediates along the hydrogen sulfide oxidatio

ISSN:0094-8276    

DOI:10.1029/GL014i002p00131

年代:1987

数据来源: WILEY