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1.
High resolution electric field and particle data, obtained by the S23L1 rocket crossing over a discrete prebreakup arc in January 1979, are studied in coordination with ground observations (Scandinavian Magnetometer Array—SMA, TV and all-sky cameras) in order to clarify the electrodynamics of the arc and its surroundings. Height-integrated conductivities have been calculated from the particle data, including the ionization effects of precipitating protons and assuming a steady state balance between ion production and recombination losses. High resolution optical information of arc location relative to the rocket permitted a check of the validity of this assumption for each flux tube passed by the rocket. Another check was provided by a comparison between calculated (equilibrium values) and observed electron densities along the rocket trajectory. A way to compensate for the finite precipitation time when calculating the electron densities is outlined. The height-integrated HalI-Pedersen conductivity ratio is typically 1.4 within the arc and about 1 at the arc edges, indicative of a relatively softer energy spectrum there. The height-integrated conductivities combined with the DC electric field measurements permitted calculation of the horizontal ionospheric current vectors (J⊥), Birkeland currents (from div J⊥) and energy dissipation through Joule heating (ΣpE2). An eastward current of typically 1 A m?1 was found to be concentrated mainly to the arc region and equatorward of it. A comparison has been made with the equivalent current system deduced from ground based magnetometer data (SMA) showing a generally good agreement with the rocket results. An intense Pedersen current peak (1.2 A m?1) was found at the southern arc edge. This edge constituted a division line between a very intense (> 10 μA m?1) and localized (~ 6 km) downward current sheet to the south, probably carried by upward flowing cold ionospheric electrons and a more extended upward current sheet (> 10 μA m?2) over the arc carried by measured precipitating electrons. Joule and particle heating across the arc were anticorrelated, consistent with the findings of Evans et al. (1977) with a total value of about 100mW m?2.  相似文献   

2.
Electron densities throughout the D- and E-regions of the ionosphere have been measured during two rocket flights from Woomera, Australia; one in the daytime and one at night. The detailed distributions have a height resolution of much better than a km over the majority of the height range which was 66–175 km on the day flight and 83–184 km at night. This resolution has enabled sharp changes in electron density to be observed such as those associated with positive ion changes near 85 km (Reid 1970) and with sporadic-E layers.The detail and large dynamic range in electron density (102 to 3 × 105 cm?3) were achieved by combining the data from an LF radio propagation experiment with those from a probe experiment. The radio equipment allowed measurement of both the phase and amplitude of the wavefield above a ground transmitter. The method of deducing electron density from the phase velocity of the penetrating component of the wavefield is explained in detail. A comparison of the probe current and electron density has shown that the ratio between them varies slowly with height.  相似文献   

3.
Soft X-ray emission from the X-ray source Per X-1 was observed in the 0.4–2 keV energy interval from a rocket borne X-ray detector. Spectral analysis of the data indicates that in the 0.4–2 keV band the X-ray emission from Per X-1 can be fitted either with a power law of slope-(4.8±1.2) or a thermal bremsstrahlung spectrum with akT value of (0.26 ?0.08 +0.12 ) keV. Such a steep spectrum is inconsistent with the spectrum measured above 2 keV. The measured flux in 0.4–2 keV band corresponds to X-ray luminosity of 3×1045 ergs s?1 for Per X-1.  相似文献   

4.
Data from eight auroral ion composition measurements, seven of which have been reported in the literature, are analyzed and compared in terms of a single model format. We find, contrary to conclusions published previously for two of the experiments, that there is no discrepancy concerning O+ ions. In general, the mean CIRA 1972 neutral model is found to be quite suitable as a representative of the major gas composition required for auroral E-region calculations which agree with the data. Nitric oxide profiles inferred from analysis of the data range from about normal non-auroral E-region nitrix oxide distributions with peak concentrations near 108 cm?3 to profiles with peak populations near 109 cm?3. Although the higher concentrations are generally correlated with intense aurora, we acknowledge that the length and strength of auroral activity prior to the individual rocket flights can have an even greater bearing, at times, on the NO “snapshot” profile deduced from the auroral ion composition data.  相似文献   

5.
Clusters of galaxies are approximated by the Schwarzschild interior solution (with non-zero cosmological constant) embedded in a Robertson/Walker background. The conditions that the two metrics join up smoothly and that the cluster be stable imply either (a)k=?1 with Λ lying in the range ?1.1×10?27?Λ?1.5×10?36 (s?2), or (b)k=0. Also, superclustering on a scale larger than 0.5 Mpc is unacceptable unless Λ<0.  相似文献   

6.
The cosmic microwave background may be explained on the basis of absorption and reemission of the light from galaxies by graphite whiskers of lengthsl?0.1-1 mm. The mass density of such particles required is of the order of 10?34 g cm?3.  相似文献   

7.
T. Iju  M. Tokumaru  K. Fujiki 《Solar physics》2013,288(1):331-353
We report radial-speed evolution of interplanetary coronal mass ejections (ICMEs) detected by the Large Angle and Spectrometric Coronagraph onboard the Solar and Heliospheric Observatory (SOHO/LASCO), interplanetary scintillation (IPS) at 327 MHz, and in-situ observations. We analyze solar-wind disturbance factor (g-value) data derived from IPS observations during 1997?–?2009 covering nearly the whole period of Solar Cycle 23. By comparing observations from SOHO/LASCO, IPS, and in situ, we identify 39 ICMEs that could be analyzed carefully. Here, we define two speeds [V SOHO and V bg], which are the initial speed of the ICME and the speed of the background solar wind, respectively. Examinations of these speeds yield the following results: i) Fast ICMEs (with V SOHO?V bg>500 km?s?1) rapidly decelerate, moderate ICMEs (with 0 km?s?1≤V SOHO?V bg≤500 km?s?1) show either gradually decelerating or uniform motion, and slow ICMEs (with V SOHO?V bg<0 km?s?1) accelerate. The radial speeds converge on the speed of the background solar wind during their outward propagation. We subsequently find; ii) both the acceleration and the deceleration are nearly complete by 0.79±0.04 AU, and those are ended when the ICMEs reach a 480±21 km?s?1. iii) For ICMEs with (V SOHO?V bg)≥0 km?s?1, i.e. fast and moderate ICMEs, a linear equation a=?γ 1(V?V bg) with γ 1=6.58±0.23×10?6 s?1 is more appropriate than a quadratic equation a=?γ 2(V?V bg)|V?V bg| to describe their kinematics, where γ 1 and γ 2 are coefficients, and a and V are the acceleration and speed of ICMEs, respectively, because the χ 2 for the linear equation satisfies the statistical significance level of 0.05, while the quadratic one does not. These results support the assumption that the radial motion of ICMEs is governed by a drag force due to interaction with the background solar wind. These findings also suggest that ICMEs propagating faster than the background solar wind are controlled mainly by the hydrodynamic Stokes drag.  相似文献   

8.
The first results of a comprehensive computer analysis of over 300 front film and grid coincidence events is presented using statistical tests on the observed data. The short term time dependence of the observed flux is entirely commensurate with a random Poisson distribution and any possible contributions from discrete “cometary showers” must certainly be of relatively minor significance compared to the sporadic background for mass > 10?13 g. Periodic seasonal variations of ～ 20 per cent of the average rate are observed common to Pioneers 8 and 9. These variations could reflect on the cometary nature of the source or alternatively indicate the presence of an interstellar component. The mass spectrum of the flux in the range 10?11?10?13 g indicates an increasing flux of particles to the lowest limits of mass detected, with a derived flux of Φ = 1·4 × 10?12m?0·68 (g) m?2 sec?1(2π ster.)?1.  相似文献   

9.
A new spectrum of Jupiter from 700 to 1600 cm?1 was obtained with an interferometric experiment using the 91.5 cm telescope of the NASA Airborne Infrared Observatory. The spectral resolution is 10 cm?1 and the signal-to-noise ratio is 30 at 900 cm?1. NH3 absorption lines are observed between 820 and 1020 cm?1. The 1306 cm?1ν4CH4 band strongly appears in emission at a temperature of at least 145° K. The Jovian brightness temperature between 1400 and 1600 cm?1, according to our measurement, is lower than 170° K.  相似文献   

10.
The High-Resolution Coronal Imager (Hi-C) was flown on a NASA sounding rocket on 11 July 2012. The goal of the Hi-C mission was to obtain high-resolution (≈?0.3?–?0.4′′), high-cadence (≈?5 seconds) images of a solar active region to investigate the dynamics of solar coronal structures at small spatial scales. The instrument consists of a normal-incidence telescope with the optics coated with multilayers to reflect a narrow wavelength range around 19.3 nm (including the Fe xii 19.5-nm spectral line) and a 4096×4096 camera with a plate scale of 0.1′′?pixel?1. The target of the Hi-C rocket flight was Active Region 11520. Hi-C obtained 37 full-frame images and 86 partial-frame images during the rocket flight. Analysis of the Hi-C data indicates the corona is structured on scales smaller than currently resolved by existing satellite missions.  相似文献   

11.
This paper discusses the experimental results on electron precipitation in a diffuse aurora obtained by a sounding rocket launched from ANDENES (L ～ 6·2) on 3 November 1968. A considerable increase in the intensity of low energy electrons, Ee ? 5 keV, followed a large precipitation of more energetic electrons Ee ? 5 keV. From the observation of angular distributions and an estimate of the diffusion coefficient (Dα ? 10?3 (sec)?2), it is suggested that this higher energy precipitation is induced by gyroresonant interactions of magnetospheric electrons with radiation in the whistler mode. The lower energy precipitation separated in time and/or space, shows quasi-periodic modulations in the 5–15 sec range with periods close to the bounce period. It is suggested that this precipitation is the result of bounce-resonance interactions with electrostatic waves in the equatorial plane. Finally, from a comparison between the experimental energy spectra and plasma sheet spectra it can be concluded that these electrons are injected from the plasma sheet during a substorm and are then diffused and precipitated by energy dependent mechanisms.  相似文献   

12.
The nitric oxide density profile between the altitudes 72 and 120 km was obtained by means of the airglow γ(1, 0) band measured with a rocket-borne radiometer flown at Syowa Station (69°S, 40°E). The NO density was found to have two peaks with a value of 1.5× 108cm?3 at 90 and 110 km, and is much larger than those in the middle and low latitudes. Because of a long lifetime of NO in the mesosphere, the observed NO enhancement may be due to the after-effect of the particle precipitation event which occurred within the half day before, despite no polar disturbance during the rocket flight.  相似文献   

13.
T. Iju  M. Tokumaru  K. Fujiki 《Solar physics》2014,289(6):2157-2175
We report kinematic properties of slow interplanetary coronal mass ejections (ICMEs) identified by SOHO/LASCO, interplanetary scintillation, and in situ observations and propose a modified equation for the ICME motion. We identified seven ICMEs between 2010 and 2011 and compared them with 39 events reported in our previous work. We examined 15 fast (V SOHO?V bg>500 km?s?1), 25 moderate (0 km?s?1≤V SOHO?V bg≤500 km?s?1), and 6 slow (V SOHO?V bg<0 km?s?1) ICMEs, where V SOHO and V bg are the initial speed of ICMEs and the speed of the background solar wind. For slow ICMEs, we found the following results: i) They accelerate toward the speed of the background solar wind during their propagation and reach their final speed by 0.34±0.03 AU. ii) The acceleration ends when they reach 479±126 km?s?1; this is close to the typical speed of the solar wind during the period of this study. iii) When γ 1 and γ 2 are assumed to be constants, a quadratic equation for the acceleration a=?γ 2(V?V bg)|V?V bg| is more appropriate than a linear one a=?γ 1(V?V bg), where V is the propagation speed of ICMEs, while the latter gives a smaller χ 2 value than the former. For the motion of the fast and moderate ICMEs, we found a modified drag equation a=?2.07×10?12(V?V bg)|V?V bg|?4.84×10?6(V?V bg). From the viewpoint of fluid dynamics, we interpret this equation as indicating that ICMEs with 0 km?s?1≤V?V bg≤2300 km?s?1 are controlled mainly by the hydrodynamic Stokes drag force, while the aerodynamic drag force is a predominant factor for the propagation of ICME with V?V bg>2300 km?s?1.  相似文献   

14.
A four-parameter model which assumes a Gaussian dependence of both temperature and pressure on distance from center is used to fit the compact part of coronal active regions as observed in X-ray photographs from a rocket experiment. The four parameters are the maximum temperature T M, the maximum pressure P M= 2NMkTM, the width of the pressure distribution σ P, and the width of the temperature distribution σ T = α1/2σP. The maximum temperature T M ranges from 2.2 to 2.8 × 106K, and the maximum density N M from 2 to 9 × 109cm?3. The range of σ P is from 2 to 4 × 109 cm and that of α from 2 to 7.  相似文献   

15.
Using formula to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15–2.4 THz frequency interval at mean temperature T=18.5 K, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure are calculated. The value for the total intensity received in the 0.15–2.4 THz frequency interval is equal to 13.6 nW?m?2?sr?1. This value is about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z=1.5.  相似文献   

16.
The peculiarities of non-Hubble bulk motions of galaxies are studied by analyzing a sample of 1271 thin edge-on spirals with distances determined using a multiparametric Tully-Fisher relation that includes the amplitude of the galaxy rotation, the blue and red diameters, surface brightness, and morphological type. In the purely dipole approximation, the bulk motion of galaxies relative to the cosmic microwave background frame can be described by the velocity of 336±96 km s?1 in the direction l=321°, b=?1° within radius R max =10000 km s?1. An analysis of more complex velocity field models shows that the anisotropy of the Hubble expansion described by the quadrupole term is equal to ～5% on scale lengths R max=6000–10000 km s?1. The amplitude within the Local Supercluster (R max=3000 km s?1) is as high as ～20%. The inclusion of the octupole component reduces the dipole amplitude to 134±111 km s?1 on scale lengths of ～8000 km s?1. The most remarkable feature of the galaxy velocity field within R max=8000 km s?1 is the zone of minimum centered on l=80°, b=0° (the constellation of Cygnus) whose amplitude reaches 18% of the mean Hubble velocity.  相似文献   

17.
From published ground-base, spacecraft, and rocket photometry and polarimetry of the zodiacal light, a number of optical and physical parameters have been derived. It was assumed that the number density, mean particle size, and albedo vary with heliocentric distance, and shown that average individual interplanetary particles have a small but definite opposition effect, a mean single-scattering albedo in the V band at 1-AU heliocentric distance of 0.09 ± 0.01, and a zero-phase geometric albedo of 0.04. Modeled by a power law, both albedos decrease with increasing heliocentric distance as r?0.54. The corresponding exponents for changes in mean particle size and number density are related in a simple way. The median orbital inclination of zodiacal light particles with respect to the ecliptic is 12°, close to the observed median value for faint asteroids and short-period comets. Furthermore, the color of dust particles and its variation with solar phase angle closely resemble those of C asteroids. These findings are, at least, consistent with the zodiacal cloud originating primarily from collisions among asteroids. Finally, a value of ?1018?ErmE g was derived for the mass of the zodiacal cloud, where ?E is the mean particle radius (in micrometers) at 1-AU-heliocentric distance. For extinction in the ecliptic, Δm = 10?5??12mag was obtained, where ? is the solar elongation in degrees.  相似文献   

18.
Altitude distributions of electronically excited atoms and molecules of oxygen and nitrogen in the aurora have been obtained by means of rocket-borne wavelength scanning interference filter photometers launched from Fort Churchill, Manitoba (58.4°N, 94.1°W) on January 23, 1974. Atomic oxygen densities derived from mass spectrometer measurements obtained during the flight are used in conjunction with the volume emission rate ratio of the N2(C3Πu?B3Πg) (0-0) second positive and N2(A3Σu+, v = 1?X1Σg+) Vegard-Kaplan bands to derive a rate constant for quenching of the N2(A3Σu+, v = 1) level with O(3P) of 1.7(±0.8) × 10?11 cm3 s?1 These data, together with O den derived from the O2(b1Σg+) state nightglow emission observed during the rocket ascent, suggest that quenching of the N2(A3Σu+, v = 1) level by O2 has a significant positive temperature dependence. The processes involved in the production and loss of the N2(A3Σu+) state are considered and energy transfer from the N2(A3Σu+) state to O(3P) is found to be a significant source of the OI 5577 Å green line in this aurora at altitudes below 130 km. Emission from the NO(A2Σ+?X2Π) gamma bands was not detected, an observation which is consistent with the mass spectrometer data obtained during the flight indicating that the NO density was <108 cm3 at 110 km. On the basis of previous rocket and satellite measurements of the NO gamma bands, energy transfer from the N2(A3Σu+) state to NO(X2Π) is shown to be an insignificant source of the gamma bands in aurora. Altitude profiles of the N2(a1Πg?X1Σg+) Lyman-Birge-Hopfield band system are presented.  相似文献   

19.
The neutral hydrogen emission at 21 cm has been investigated with the RATAN-600 radio telescope in the vicinity of the supernova remnant HB9. A clumpyHI shell with radial motions surrounding the remnant has been detected. Its measured parameters contradict the connection with a shock wave from a supernova explosion. The shell formation under the action of a wind from a star that exploded as a supernova at the end of its evolution seems more realistic. The characteristics of the star obtained from the observed shell parameters are the following: a wind power of 0.5 × 1038 erg s?1, a mass-loss rate of 3.7 × 10?5 M ⊙ yr?1, and an age of 3 × 106 yr. Given the measurement errors, the mass of the star is estimated to be >8M ⊙.  相似文献   

20.
The orbit of Cosmos 482 has been determined at 55 epochs during the period August 1975–October 1977. Inclined at 52° to the Equator, of eccentricity exceeding 0.3 and perigee height near 210 km, this high drag and high eccentricity orbit is the most eccentric as yet analysed by PROP. The combination of the orbital characteristics, restricted global coverage of observational data, and the many observations of angular measurement at extreme range proved to be troublesome. Cleared of other perturbations, the inclination is analysed to determine the atmospheric rotation rate, λ rev day?1, of the zonal winds at a height near 235 km. Results reveal a diurnal and seasonal dependence, including a summer value, averaged over local time, of λ = 0.9 and an evening value of λ = 1.4 in the winter months. The resultant wind velocities vary between 48 m s?1 East to West and 193 m s?1 West to East, with an average of 48 m s?1 West to East.  相似文献   

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