Magnetospheric solitary structure maintained by 3000 km/s ions as a cause of westward moving auroral bulge at 19 MLT

Abstract. In the evening equatorial magnetosphere at about 4 RE geocentric distance and 19 MLT, the four Cluster spacecraft observed a solitary structure with a width of about 1000~2000 km in the propagation direction. The solitary structure propagates sunward with about 5~10 km/s carrying sunward electric field (in the propagation direction) of up to about 10 mV/m (total potential drop of about 5~10 kV), depletion of magnetic field of about 25%, and a duskward E×B convection up to 50 km/s of He+ rich cold plasma without O+. At the same time, auroral images from the IMAGE satellite together with ground based geomagnetic field data showed a westward (sunward at this location) propagating auroral bulge at the magnetically conjugate ionosphere with the solitary structure. The solitary structure is maintained by flux enhancement of selectively 3000 km/s ions (about 50 keV for H+, 200 keV for He+, and 750 keV for O+). These ions are the main carrier of the diamagnetic current causing the magnetic depletion, whereas the polarization is maintained by different behavior of energetic ions and electrons. Corresponding to aurora, field-aligned accelerated ionospheric plasma of several keV appeared at Cluster from both hemispheres simultaneously. Together with good correspondence in location and propagation velocity between the auroral bulge and the solitary structure, this indicates that the sunward moving auroral bulge is caused by the sunward propagation of the solitary structure which is maintained by energetic ions. The solitary structure might also be the cause of Pi2-like magnetic variation that started simultaneously at Cluster location.

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THE EFFECTS OF POLARIZATION UPON THE STEEL WIRE-NITRIC ACID MODEL OF NERVE ACTIVITY

The Journal of General Physiology ◽

10.1085/jgp.11.2.159 ◽

1927 ◽

Vol 11 (2) ◽

pp. 159-174 ◽

Cited By ~ 5

Author(s):

George H. Bishop

Keyword(s):

Nitric Acid ◽

Protective Coatings ◽

Steel Wire ◽

Potential Drop ◽

Electrochemical Protection ◽

Total Potential ◽

Oxidation Reduction ◽

Refractory State ◽

Passivation Potential ◽

Potential Equilibrium

The active process in a short length of steel wire passivated by 65 per cent nitric acid has been observed under the influence of a polarizing current, and the form of the potential recorded by the cathode ray oscillograph. In the passive wire, 80 per cent of the total potential drop takes place at the anode, 20 per cent at the cathode. The change from active to passive states, as measured by the potential change, is very abrupt compared to the duration of activity and the potential curve at a point on the wire is probably almost rectangular. The duration of the refractory state is decreased at the anode and increased at the cathode, as in nerve. This fact is against the idea that reactivity after passivation results from a partial reduction of an oxide layer. Soft iron wire passivated by anodal polarization repassivates after activation in acid of a dilution that fails to passivate it initially. It soon becomes rhythmic with a very short refractory phase, and then reacts continuously. Such a wire exhibits a very sharp alternation between a dark brown oxide coat during activity, and a bright clean surface during passivation. A passive steel wire in nitric acid shows many of the characteristics of an inert electrode such as platinum, and it may be inferred that, superposed upon the primary passivation potential, there exists an electrode or oxidation-reduction potential equilibrium between the effects of the various constituents of the solution. It is suggested that the phenomena of nerve-like reactivity in this system may involve an alternation between two protective coatings of the steel wire. During activity, the surface becomes mechanically coated with a brown oxide. If this coating does not adhere, due to gas convection or to rapid solution of the oxide, passivation does not result. Under sufficiently intense oxidizing conditions, a second oxide coat may form in the interstices of the first, and cover the surface as the first coating dissolves off. This furnishes the electrochemical protection of passivation, which is followed by the gradual attainment of electrode equilibrium with the solution.

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Current-voltage curves for ion-exchange membranes. Contributions to the total potential drop

Journal of Membrane Science ◽

10.1016/0376-7388(91)80014-w ◽

1991 ◽

Vol 61 ◽

pp. 177-190 ◽

Cited By ~ 32

Author(s):

V.M. Aguilella ◽

S. Mafe ◽

J.A. Manzanares ◽

J. Pellicer

Keyword(s):

Ion Exchange ◽

Potential Drop ◽

Ion Exchange Membranes ◽

Total Potential ◽

Current Voltage

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Minimization of self-potential survey mis-ties acquired with multiple reference locations

Geophysics ◽

10.1190/1.2829390 ◽

2008 ◽

Vol 73 (2) ◽

pp. F71-F81 ◽

Cited By ~ 12

Author(s):

Burke J. Minsley ◽

Darrell A. Coles ◽

Yervant Vichabian ◽

Frank Dale Morgan

Keyword(s):

Potential Field ◽

Measurement Errors ◽

Computational Cost ◽

Potential Drop ◽

Iterative Solution ◽

Data Set ◽

Loop Closure ◽

Total Potential ◽

Self Potential ◽

Unique Potential

Self-potential (SP) surveys often involve many interconnected lines of data along available roads or trails, with the ultimate goal of producing a unique map of electric potentials at each station relative to a single reference point. Multiple survey lines can be tied together by collecting data along intersecting transects and enforcing Kirchhoff’s voltage law, which requires that the total potential drop around any closed loop equals zero. In practice, however, there is often a nonzero loop-closure error caused by noisy data; traditional SP processing methods redistribute this error evenly over the measurements that form each loop. The task of distributing errors and tying lines together becomes nontrivial when many lines of data form multiple interconnected loops because the loop-closure errors are not independent, and a unique potential field cannot be determined by processing lines sequentially. We present a survey-consistent processing method that produces a unique potential field by minimizing the loop-closure errors over all lines of data simultaneously. When there are no interconnected survey loops, the method is equivalent to traditional processing schemes. The task of computing the potential field is posed as a linear inverse problem, which easily incorporates prior information about measurement errors and model constraints. We investigate the use of both [Formula: see text] and [Formula: see text] measures of data misfit, the latter requiring an iterative-solution method with increased computational cost. The [Formula: see text] method produces more reliable results when outliers are present in the data, and is similar to the [Formula: see text] result when only Gaussian noise is present. Two synthetic examples are used to illustrate this methodology, which is subsequently applied to a field data set collected as part of a geothermal exploration campaign in Nevis, West Indies.

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Divalent Ion-Specific Outcomes on Stern Layer Structure and Total Surface Potential at the Silica:Water Interface

10.33774/chemrxiv-2021-s1bbw ◽

2021 ◽

Author(s):

Emily Ma ◽

Franz Geiger

Keyword(s):

Layer Structure ◽

Divalent Cations ◽

Potential Drop ◽

Fused Silica ◽

Interfacial Structure ◽

Nonlinear Susceptibility ◽

Stern Layer ◽

Phase Measurements ◽

Total Potential ◽

Interfacial Potential

The second-order nonlinear susceptibility, chi(2), in the Stern layer, and the total interfacial potential drop, Phi(0)tot, across the oxide:water interface are estimated from SHG amplitude and phase measurements for divalent cations (Mg2+, Ca2+, Sr2+, Ba2+) at the silica:water interface at pH 5.8 and various ionic strengths. We find that interfacial structure and total potential depend strongly on ion valency. We observe statistically significant differences between the experimentally determined chi(2) value for NaCl and that of the alkali earth series, but smaller differences between ions of the same valency in that series. These differences are particularly pronounced at intermediate salt concentrations, which we attribute to the influence of hydration structure in the Stern layer. Furthermore, we corroborate the differences by examining the effects of anion substitution (SO4 2- for Cl-). Finally, we identify that hysteresis in measuring the reversibility of ion adsorption and desorption at fused silica in forward and reverse titrations manifests itself both in Stern layer structure and in total interfacial potential for some of the salts, most notable CaCl2 and MgSO4, but less so for BaCl2 and NaCl.

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An Electrochemical Study of Aluminum Corrosion in Boiling High Purity Water

CORROSION ◽

10.5006/0010-9312-23.12.365 ◽

1967 ◽

Vol 23 (12) ◽

pp. 365-370 ◽

Cited By ~ 1

Author(s):

R. A. LEGAULT ◽

J. E. DRALEY

Keyword(s):

Experimental Data ◽

Protective Layer ◽

Potential Drop ◽

R And D ◽

Total Potential ◽

A Value ◽

Wide Range ◽

Aluminum Corrosion ◽

Simplifying Assumptions

Abstract An equation relating current and electrochemical potential has been derived on the basis of a physical model of the corrosion process. In the model, the total potential drop from metal to solution is the sum of potential contributions arising from the interfacial reactions at the metal-oxide and oxide-solution interfaces and that which derives from the transport of charged species through the film. On the basis of some simplifying assumptions, the derived equation reduces to ΔE = IR + Ksℓn (1 + ID), where R and D are complex constants and Ks is equal to RT/αzF for the liberation of hydrogen at the surface of the protective layer. This equation has been fitted successfully to experimental data. Assigning the value usually attributed to α for the hydrogen reaction, 1/2, optimum values of the constants were found to vary reasonably with time. If a value of α is not assigned, the equation can be fitted to experimental data over a wide range of values for the three constants. Polarization measurements alone are not sufficient to determine unequivocal values for the constants, hence a determination of the mechanism of the aqueous oxidation of aluminum will require additional independent measurements.

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Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

Annales Geophysicae ◽

10.5194/angeo-22-3099-2004 ◽

2004 ◽

Vol 22 (9) ◽

pp. 3099-3107 ◽

Cited By ~ 32

Author(s):

T. J. Immel ◽

H. U. Frey ◽

S. B. Mende ◽

E. Sagawa

Keyword(s):

Electric Fields ◽

Ionospheric Plasma ◽

Global Scale ◽

Local Times ◽

Plasma Bubbles ◽

Plasma Drift ◽

Image Satellite ◽

Far Ultraviolet ◽

Longitudinal Variability

Abstract. Space-based measurements from an imager aboard the high-apogee NASA-IMAGE satellite allows for global-scale observations of nightside ionospheric densities and structure. Such a view cannot be provided by imagers in near-Earth orbit or based on the ground. The IMAGE Spectroscopic Imager (SI) isolates the Far-ultraviolet (FUV) O I 135.6nm emission which is produced through radiative recombination of O+. These observations clearly show the distribution of FUV emissions of the equatorial airglow bands over the range of local times between the evening terminator to points well after midnight. Determination of plasma drift speeds in these local time sectors is performed by identification and subsequent tracking of localized depressions in the FUV emissions. This determination is made for nearly 200 plasma bubbles in the March-May period of 2002. Important findings of this study include (1) an unambiguous association between Dst and zonal plasma drift speeds, and (2) a longitudinal dependence of the zonal plasma drift speeds, with a peak around the Indian sector. The first effect is attributed to penetrating ring current electric fields, while the second is apparently due to a longitudinal variability in the vertical polarization electric fields that directly affects the zonal plasma drift speeds.

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The influence of the underlying surface on the cataphoretic mobility of adsorbed proteins

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1933.0176 ◽

1933 ◽

Vol 142 (847) ◽

pp. 382-401 ◽

Cited By ~ 10

Keyword(s):

Double Layer ◽

Solid Surface ◽

Electrical Double Layer ◽

Electrokinetic Potential ◽

Potential Drop ◽

Diffuse Layer ◽

Exact Relation ◽

Total Potential ◽

Adsorbed Proteins ◽

The Relationship

Our knowledge of the structure of the electrical double layer at the interface between a solid and a liquid is so indefinite that it is difficult to give a precise definition or to make an exact measurement of electrokinetic potential. In the liquid in the immediate vicinity of the solid surface, there will be an excess of ions of opposite charge to that on the surface, forming an electrical double layer which is approximately a molecular diameter in thickness. All the potential drop, however, is not confined to this first double layer ; the excess ions in the solution are not rigidly held to the surface, they are able to break away and to form a diffuse layer which extends some distance into the solution. Experience has shown that gentle stirring of the solution can influence the distribution of these ions, and it is probable that the diffuse layer extends as far as 10 -5 to 10 -4 cm. from the solid surface. It is this diffuse layer of more or less loosely held ions which is responsible for the electrokinetic properties of liquids in contact with solid surfaces. No exact relation has been established connecting the diffuse, or electrokinetic potential, with the total potential drop between a solid and a liquid. Usually they are of the same sign, but there is evidence that the potential drop across the diffuse layer can even be opposite in sign from the main potential, indicating a twofold double layer. The presence of polar molecules adsorbed at the interface may have a profound effect on the distribution of the diffuse layer without sensibly affecting the total potential difference. Further work on the relationship between these quantities would be valuable.

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Methionine-Specific Staining of Collagen

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005408x ◽

1982 ◽

Vol 40 ◽

pp. 294-295

Author(s):

E.M. Kuhn ◽

K.D. Marenus ◽

M. Beer

Keyword(s):

Amino Acids ◽

Collagen Fibers ◽

Type Iii Collagen ◽

Type I ◽

Electron Microscopic ◽

Good Correspondence ◽

Specific Staining ◽

Type Iii ◽

Different Types ◽

Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

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