Wind Asymmetry Research Articles

The interstellar wind as a cause for longitudinal solar wind asymmetries

We show here that the relative motion of the solar system with respect to the ambient interstellar plasma enforces a clearly pronounced upwind/downwind momentum flow asymmetry in the shocked solar wind. With the help of an analytic description of this subsonic flow regime taken from Parker (1963, Interplanetary Dynamical Processes. Interscience, New York) we were able to quantitatively determine the expected momentum flow asymmetries and the forces exerted on closed surfaces from which such a flow is originating. Assuming that the up/down asymmetry can be forwarded from the subsonic to the supersonic solar wind through the heliospheric shock by that wind component behaving subsonically everywhere, i.e. electrons, we arrive at corresponding asymmetric outer boundary conditions which the adapted supersonic solar wind solutions have to match. We shall prove in this paper that via the subsonic solar wind electrons, the solar wind expansion actually realized can be strongly influenced by the asymmetric outside LISM momentum flow conditions. Though this situation cannot be consistently treated with existing solar wind models, we nevertheless want to give an idea of its consequences. With the help of a conventional two fluid solar wind model we produce such solutions here that in a quantitative form show longitudinal solar wind asymmetries even in the region between the coronal basis and the Earth's orbit. In order to confirm the existence of such asymmetries we propose to monitor the solar wind momentum flow along the orbit of the Earth. We also calculate the braking rate of the solar system connected with such a momentum flow.

The causes and consequences of phase unbalance in single-sided linear induction motors

Unbalance in the phase currents of a single-sided linear induction motor (LIM) under balanced voltage operation is due to asymmetry of the primary windings and to the longitudinal end effect. Two methods of evaluating phase unbalance are presented. The first is analytical and is based on an equivalent circuit model. The second approach is numerical and uses the finite-element method. Computational results are validated by comparison with test results on a large-scale single-sided LIM. It is shown that phase unbalance produces a reduction in both thrust and normal forces, but this effect is likely to be significant only for high-speed LIMs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

F region ion temperature enhancements resulting from Joule heating

F region ion temperature measurements were made by the Chatanika and Millstone Hill incoherent scatter radars as part of the Magnetosphere‐Ionosphere‐Thermosphere Radar Studies program of coordinated high‐latitude observations. At both radars, periods of enhanced ion temperature associated with Joule heating events were detected. A regular feature of the observations was the existence of larger and longer lasting temperature enhancements in the morning sector as contrasted with the evening sector during periods of comparable electric field magnitudes. Because the ion temperature increases in proportion to the square of the vector difference between the ion and neutral velocities, the morning/evening temperature enhancement asymmetry implies a morning/evening neutral wind asymmetry. The neutral wind in the evening must be more closely aligned to the ion flow vector. This might arise as a consequence of the higher plasma density in the evening sector, enabling the ions to set the neutral air in motion. Comparison of the simultaneous plasma density and ion velocity measurements with the ion temperature data supports the foregoing explanation for the observed greater morning sector temperature enhancements.

NON-TRANSFORMATIONAL MATRIX ANALYSIS OF ELECTRICAL MACHINERY

ABSTRACT The general theory of electrical machines based on space phasor representation of space waves is explained. Harmonics of both the winding distribution and air-gap irregularities are taken into account for any winding asymmetry. Complex winding factors, symmetrical components of instantaneous values, and the winding inductances referring to the air-gap field are obtained during derivation of equation without the use of transformations. All quantities involved are physically defined. The method represents a common basis for analysis and design.

Polar enhancements of interplanetary L-alpha through solar wind asymmetries

Polar enhancements of interplanetary L-alpha through solar wind asymmetries

A graphic solution for wave velocities of sound in crystals: Bond, W.L., Vol 48, No 5 (November 1970) pp1084–1085

In this study we have used VHF and GPS-SCINDA receivers located at Nairobi (36.8°E, 1.3°S, dip −24.1°) in Kenya, to investigate the ionospheric scintillation and zonal drift irregularities of a few hundred meter-scale irregularities associated with equatorial plasma density bubbles for the period 2011. From simultaneous observations of amplitude scintillation at VHF and L-band frequencies, it is evident that the scintillation activity is higher during the post sunset hours of the equinoctial months than at the solstice. While it is noted that there is practically no signatures of the L-band scintillation in solstice months (June, July, December, January) and after midnight, VHF scintillation does occur in the solstice months and show post midnight activity through all the seasons. VHF scintillation is characterized by long duration of activity and slow fading that lasts till early morning hours (05:00 LT). Equinoctial asymmetry in scintillation occurs with higher occurrence in March–April than in September–October. The occurrence of post midnight VHF scintillation in this region is unusual and suggests some mechanisms for the formation of scintillation structure that might not be clearly understood. Zonal drift velocities of irregularities were measured using cross-correlation analysis with time series of the VHF scintillation structure from two closely spaced antennas. Statistical analyses of the distribution of zonal drift velocities after sunset hours indicate that the range of the velocities is 30–160 m/s. This is the first analysis of the zonal plasma drift velocity over this region. Based on these results we suggest that the east–west component of the plasma drift velocity may be related to the evolution of plasma bubble irregularities caused by the prereversal enhancement of the eastward electric fields. The equinoctial asymmetry of the drift velocities and scintillation could be attributed to the asymmetry of neutral winds in the thermosphere that drives the eastward electric fields.

Mechanical or electromechanical resonance: Jagodzinski, Z. Vol 23, No 6 (December 1970) pp355–361

In this study we have used VHF and GPS-SCINDA receivers located at Nairobi (36.8°E, 1.3°S, dip −24.1°) in Kenya, to investigate the ionospheric scintillation and zonal drift irregularities of a few hundred meter-scale irregularities associated with equatorial plasma density bubbles for the period 2011. From simultaneous observations of amplitude scintillation at VHF and L-band frequencies, it is evident that the scintillation activity is higher during the post sunset hours of the equinoctial months than at the solstice. While it is noted that there is practically no signatures of the L-band scintillation in solstice months (June, July, December, January) and after midnight, VHF scintillation does occur in the solstice months and show post midnight activity through all the seasons. VHF scintillation is characterized by long duration of activity and slow fading that lasts till early morning hours (05:00 LT). Equinoctial asymmetry in scintillation occurs with higher occurrence in March–April than in September–October. The occurrence of post midnight VHF scintillation in this region is unusual and suggests some mechanisms for the formation of scintillation structure that might not be clearly understood. Zonal drift velocities of irregularities were measured using cross-correlation analysis with time series of the VHF scintillation structure from two closely spaced antennas. Statistical analyses of the distribution of zonal drift velocities after sunset hours indicate that the range of the velocities is 30–160 m/s. This is the first analysis of the zonal plasma drift velocity over this region. Based on these results we suggest that the east–west component of the plasma drift velocity may be related to the evolution of plasma bubble irregularities caused by the prereversal enhancement of the eastward electric fields. The equinoctial asymmetry of the drift velocities and scintillation could be attributed to the asymmetry of neutral winds in the thermosphere that drives the eastward electric fields.

Optical measurements of ultrasonic attenuation and reflection losses in fused silica: Krischer, C., Vol 48, No 5 (November 1970) pp1085–1092

In this study we have used VHF and GPS-SCINDA receivers located at Nairobi (36.8°E, 1.3°S, dip −24.1°) in Kenya, to investigate the ionospheric scintillation and zonal drift irregularities of a few hundred meter-scale irregularities associated with equatorial plasma density bubbles for the period 2011. From simultaneous observations of amplitude scintillation at VHF and L-band frequencies, it is evident that the scintillation activity is higher during the post sunset hours of the equinoctial months than at the solstice. While it is noted that there is practically no signatures of the L-band scintillation in solstice months (June, July, December, January) and after midnight, VHF scintillation does occur in the solstice months and show post midnight activity through all the seasons. VHF scintillation is characterized by long duration of activity and slow fading that lasts till early morning hours (05:00 LT). Equinoctial asymmetry in scintillation occurs with higher occurrence in March–April than in September–October. The occurrence of post midnight VHF scintillation in this region is unusual and suggests some mechanisms for the formation of scintillation structure that might not be clearly understood. Zonal drift velocities of irregularities were measured using cross-correlation analysis with time series of the VHF scintillation structure from two closely spaced antennas. Statistical analyses of the distribution of zonal drift velocities after sunset hours indicate that the range of the velocities is 30–160 m/s. This is the first analysis of the zonal plasma drift velocity over this region. Based on these results we suggest that the east–west component of the plasma drift velocity may be related to the evolution of plasma bubble irregularities caused by the prereversal enhancement of the eastward electric fields. The equinoctial asymmetry of the drift velocities and scintillation could be attributed to the asymmetry of neutral winds in the thermosphere that drives the eastward electric fields.

Solstitial Sq-currents through the magnetosphere

Starting from a theoretically derived expression for the density of the electric current which escapes upwards from the ionosphere, the S q -currents which flow along the magnetic lines of force through the magnetosphere as a consequence of the asymmetry in conductivity between the northern- and southern hemispheres have been computed for the month June 1958. The result is a current of 30,000 A, passing through the magnetosphere from North to South in the morning sector and back in the afternoon sector. A current of this type will always be present during solsticies, but it will be superposed by a current, caused by the asymmetry of the ionospheric winds, which is as yet of unknown type. From an order of magnitude calculation it is concluded that the latter current will generally dominate.

Effects of asymmetry of induction-machine windings upon the slot leakage reactance

It has been shown recently that asymmetrical fractional-slot windings can be devised to draw balanced currents. The leakage reactance for the three phases of these windings may, however, no longer be equal. The paper discusses the effects of the asymmetry of the windings upon one component of leakage, namely the slot leakage. It is shown that, by careful selection of the coil pitch for the winding, equal slot leakages are possible for the three phases. The paper also suggests how the slot leakage reactance may be determined for other coil pitches.