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  • 1
    Electronic Resource
    Electronic Resource
    Alfvenic fluctuations in the solar wind: A case study using Ulysses measurements (1995)
    Springer
    Space science reviews 72 (1995), S. 197-200 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present preliminary results of a study of solar wind Alfvénic fluctuations using magnetometer and plasma measurements from the spacecraft Ulysses. We focus on a particular case study, and use ‘wave language’ to discuss the fluctuations. The observations are consistent with a mixture of convected structures and Alfvén wave trains. Furthermore, our results tend to suggest that the Alfvénic-fluctuations propagate in the radial direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00768779
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  • 2
    Electronic Resource
    Electronic Resource
    Solar wind heavy ion abundances (1975)
    Springer
    Solar physics 43 (1975), S. 463-473 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract During periods in 1969–1971 when interplanetary flow conditions were quiet, 17 determinations of the solar wind Fe and Si abundances and 7 of the O abundance were made. On the average 〈N(Fe)/N(H)〉 = 5.3 × 10-5, 〈N(Si)/N(H)〉 = 7.6 × 10-5 and 〈N(O)/N(H)〉 = 5.2 × 10-4. Variations from the averages over a total range of factors of ∼4 for O, ∼4 for Si, and ∼ 10 for Fe have have observed. Although Fe and Si abundance variations appear to be correlated, no other element correlation pairs are unambiguously discernible from the present data set.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152368
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  • 3
    Electronic Resource
    Electronic Resource
    The quiet corona: Temperature and temperature gradient (1974)
    Springer
    Solar physics 35 (1974), S. 137-152 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study of the lower corona thermal properties was made using the best examples of solar wind heavy ion spectra obtained with Vela 5 and 6 plasma analyzers at times of quiet solar wind (low speed, low temperature). The multiple Si and Fe ion species peaks in the spectra were fit with solutions of the ionization equilibrium equations to determine ‘freezing in’ temperatures for the various species over a range of heliocentric distances r. Assuming a power law electron temperature model, T = =t ⊙ (R ⊙/r) α , spherical symmetry, and mass conservation, the following results for the quiet corona were obtained: (1) The average freezing in temperatures ranged near 1.5 × 106 K at r ∼- 2.4 to 3.9 R ⊙. (2) Values for T ⊙ ranged between 1.7 × 106 K and 2.5 × 106 K with an average of 1.84 ± 0.13 × 106 K. (3) The temperature gradient parameter α lay between 0.20 and 0.41 with an average value of 0.29 ± ±0.06. This is consistent with the predicted value α = 2/7 derived from conduction dominated spherically symmetric models of the corona. (4) The 0 and N lines which freeze in at a distance of r ∼-1.5 R ⊙ indicate temperatures of ∼ 2.1 × 106 K. Temperatures higher at 1.5 R ⊙ than at 3 R ⊙, in agreement with extrapolations of the power law model, suggest that coronal heating in regions of open field geometry is not important beyond r ∼- 1.5 R ⊙.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00156963
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  • 4
    Electronic Resource
    Electronic Resource
    Solar wind heavy ions from flare-heated coronal plasma (1979)
    Springer
    Solar physics 62 (1979), S. 179-201 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Information concerning the coronal expansion is carried by solar wind heavy ions. Distinctly different energy-per-charge ion spectra are found in two classes of solar wind having the low kinetic temperatures necessary for E/q resolution of the ion species. Heavy ion spectra which can be resolved are most frequently observed in the low-speed interstream (IS) plasma found between high speed streams; the streams are thought to be coming from coronal holes. Although the sources of the IS plasma are uncertain, the heavy ion spectra found there contain identifiable peaks of O, Si, and Fe ions. Such spectra indicate that the IS ionization state of O is established in coronal gas at T ≈ 2.1 × 106 K while that of Fe is frozen in farther out at ∼1.5 × 106 K. On occasion anomalous spectra are found outside IS flows in solar wind with abnormally depressed local kinetic temperatures. The anomalous spectra contain Fe16+ ions, not usually found in IS flows, and the derived coronal freezing in temperatures are significantly higher; for two of the best cases values of ∼3.4 × 106 K were found for the O ions and ∼2.9 × 106 K for Fe ions. The coronal sources of some of these ionizationally hot flows are identified as solar flares. The appearance of abnormally depressed kinetic temperatures in solar wind coming from flare-heated coronal gas lends support to earlier speculation that flares can expel plasma enclosed in magnetic bottles or bubbles. In transit to 1 AU the gas is sufficiently isolated from the hot corona that it cools anomalously. The Los Alamos Scientific Laboratory requests that the publisher identify this article as work performed under the auspices of the Department of Energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00150143
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  • 5
    Electronic Resource
    Electronic Resource
    Relation between superheating and superacceleration of helium in the solar wind (1979)
    Springer
    Solar physics 63 (1979), S. 201-205 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Solar-wind data obtained by the OGO-5 and IMP-6-8 Earth satellites show a positive correlation between the ratio of helium to hydrogen temperatures, T α/T p, and the velocity difference between the two ions, v α - v p . Although this result disagrees with the Prognoz-1 results reported earlier in this journal, it is consistent with the expected control by Coulomb collisions when the solar-wind density is high.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00155710
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  • 6
    Electronic Resource
    Electronic Resource
    Helium abundance variations in the solar wind (1983)
    Springer
    Solar physics 83 (1983), S. 367-378 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Helium abundance variations in the solar wind have been studied using data obtained with Los Alamos plasma instrumentation on IMP 6, 7, and 8 from 1971 through 1978. For the first time, average flow characteristics have been determined as a function of helium abundance, A(He). Low and average values of A(He) are each preferentially identified with a different characteristic plasma ‘state’ these correspond to what have previously been recognized as the signatures of interplanetary magnetic field polarity reversals and high speed streams, respectively. Helium enhancements at 1 AU also can be identified with a characteristic plasma state, which includes high magnetic field intensity and low proton temperature. This is further evidence that such enhancements are a signal of coronal transient mass ejections. Long-term averages of A(He) at least partially reflect the relative frequency with which coronal streamers, holes, and transients extend their influence into the ecliptic plane at 1 AU. As a result, there is a real and pronounced solar cycle variation of solar wind H(He).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00148286
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  • 7
    Electronic Resource
    Electronic Resource
    Abundance differences in solar wind double streams (1974)
    Springer
    Solar physics 37 (1974), S. 451-467 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Eight examples of persistent double ion streams with simultaneously resolved protons and alpha particles have been found in the 1971 and 1972 data from the Los Alamos plasma analyzer on IMP 6. The proton streams are observed to have greater velocity separations than their alpha particle counterparts and the secondary stream is the higher velocity stream in each of these examples. Helium to hydrogen abundance ratios for the two streams observed simultaneously differ by up to a factor of ∼ 4; the average is 2.3. The secondary, higher velocity stream usually has the larger fraction of helium. Selection criteria may bias these results to some degree. Observations of double streams at 1 AU with large abundance differences in the separate streams provide evidence that their origin is in a corona with an inhomogeneous distribution of helium, although the evidence may not be considered conclusive at present. Several conceptual models are suggested for the formation of double streams which account for these abundance differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152503
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  • 8
    Electronic Resource
    Electronic Resource
    Coronal holes, solar wind streams, and recurrent geomagnetic disturbances: 1973–1976 (1976)
    Springer
    Solar physics 49 (1976), S. 271-278 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Observations of coronal holes, solar wind streams, and geomagnetic disturbances during 1973–1976 are compared in a 27-day pictorial format which shows their long-term evolution. The results leave little doubt that coronal holes are related to the high-speed streams and their associated recurrent geomagnetic disturbances. In particular, these observations strongly support the hypothesis that coronal holes are the solar origin of the high-speed streams observed in the solar wind near the ecliptic plane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00162451
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