Large velocity discontinuities in the solar wind     

Leonard F. Burlaga 《Solar physics》1969,7(1):72-86

In the course of 3000 hours observation of the interplanetary plasma, the plasma and magnetic-field experiments on Explorer 34 have detected 11 discontinuous solar-wind speed changes, not associated with shocks, of more than 60 km/sec in less than 3 min. These events, called uD's, may show a velocity change of either sign, but the plasma density and temperature are not found to change appreciably across them. Each speed discontinuity occurs simultaneously with a directional discontinuity in the magnetic field. High-resolution magnetic-field data show that sometimes the directional changes occur as rotational fans, and at other times they are erratic or occur within the time resolution of the magnetic-field experiment, 2.6 sec. The flow direction of the solar wind changed at 2 of the 11 uD's. The quiet nature of the field and plasma on each side of these events gives the impression that they are stable. The existence of these uD's is shown to be consistent with the theory of the Helmholtz instability. In particular, the additional observation that the magnetic-field direction change, , at a uD tends to be near 90° is consistent with the theory, for uD's with small may become unstable as they move from the sun.  相似文献   

Energy losses of low-energy photoelectrons to thermal electrons     

Robert W. Schunk  Paul B. Hays 《Planetary and Space Science》1971

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Spectroscopic determinations of solar rotation   总被引：2，自引：0，他引：2  

Robert Howard  J. Harvey 《Solar physics》1970,12(1):23-51

Spectral line shift data obtained from full-disk magnetograms recorded at Mt. Wilson are analyzed for differential rotation. The method of analysis is discussed and the results from the data for 1966 through 1968 are presented. The average equatorial velocity over this period is found to be 1.93 km/sec or 13.76 deg/day (sidereal). This corresponds to a sidereal period of 26.16 days. The average results are = 2.78 × 10^-6 - 3.51 × 10^-7 sin² B - 4.43 × 10^-7 sin⁴ B rad/sec, whereB is the solar latitude. This indicates a smaller decrease of angular velocity with latitude than found by earlier investigators. Variations from day to day are caused by large-scale short-lived velocity fields on the solar surface. There also appear to be secular variations.Currently at the Kitt Peak National Observatory, Tucson, Arizona.  相似文献   

    

W. A. Heiskanen  J. Lamar Worzel  G. Lynn Shurbert  Paul Herget  Clair E. Ewing  Carl I. Aslakson  Simo Laurila  John R. Williams  David T. Williams  Bertil Hallert  Robert C. Fitzpatrick  W. M. Markowitz  S. P. Worden  Henry Wild Jr  W. Kneissl 《Journal of Geodesy》1955,29(2):55-78

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Diagenetic sulfate reduction in marine sediments     

Robert E. Sweeney  I.R. Kaplan 《Marine Chemistry》1980,9(3):165-174

The importance of interstitial pore water as a vehicle for transport of dissolved ions between sediment at depth and the overlying ocean reservoir may be overestimated. The major cause of this overestimation is the assumption that the rate of ionic diffusion through the sediment is of a similar magnitude to the rate of reaction occurring within the sediment column. Examples are given to indicate that the above assumption may not be correct, at least for diagenetic sulfate reduction. Closed-system modeling, although approximate, is shown to be consistent, both qualitatively and isotopically, with measured changes that are observed for several sedimentary environments.  相似文献   

Methods of foundation engineering.—Developments in geotechnical Engineering, 24 | Z. Bazˇant. Elsevier,Amsterdam, 1979, 616 pp., U.S. $ 90.25, Dfl. 185.00     

Robert L. Lytton 《Engineering Geology》1981,17(4):284-285

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Editorial     

Cornelis de Jager  Robert F. Howard  ZdenĚk švestka 《Solar physics》1993,143(1):vii-vii

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On the correlation of longitudinal and latitudinal motions of sunspots     

Peter A. Gilman  Robert Howard 《Solar physics》1984,93(1):171-175

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A STATISTICAL APPROACH TO THE PROBLEM OF MISSING SPATIAL DATA USING A FIRST-ORDER MARKOV MODEL*     

Robert Haining  Daniel A. Griffith  Robert Bennett 《The Professional geographer》1984,36(3):338-345

Geographical data sets sometimes contain missing observations that need to be estimated. A statistical approach to the problem is discussed for multivariate normal spatial data sets satisfying the first-order spatial Markov property with constant mean, where the information at neighboring or contiguous observed sites is used to estimate the missing values. The completed data are used to estimate the parameters of the distribution. The procedure is iterative. The approach is a special case of the Orchard and Woodbury missing information principle. The paper concludes with an illustrative empirical example using rainfall data from an area of Kansas and Nebraska. The quality of the estimates for different sites are compared.  相似文献   

Fast solar electrons,interplanetary plasma and km-wave type-III radio bursts observed from the IMP-6 spacecraft     

Hector Alvarez  Robert P. Lin  Samuel J. Bame 《Solar physics》1975,44(2):485-501

IMP-6 spacecraft observations of low frequency radio emission, fast electrons, and solar wind plasma are used to examine the dynamics of the fast electron streams which generate solar type-III radio bursts. Of twenty solar electron events observed between April, 1971 and August, 1972, four were found to be amenable to detailed analysis. Observations of the direction of arrival of the radio emission at different frequencies were combined with the solar wind density and velocity measurements at 1 AU to define an Archimedean spiral trajectory for the radio burst exciter. The propagation characteristics of the exciter and of the fast electrons observed at 1 AU were then conpared. We find that: (1) the fast electrons excite the radio emission at the second harmonic; (2) the total distance travelled by the electrons was between 30 and 70% longer than the length of the smooth spiral defined by the radio observations; (3) this additional distance travelled is the result of scattering of the electrons in the interplanetary medium; (4) the observations are consistent with negligible true energy loss by the fast electrons.  相似文献