This paper describes a coordinated rocket and ground-based study to investigate equatorial spread F irregularities. Measurements by the Jicamarca backscatter radar, ionosondes, and airglow instrumentation and of radio scintillations were correlated with high spatial resolution measurements of electron densities, particle fluxes, and VLF-ELF fields from a rocket probe. Experimentally, we find that (l) very high positive and negative electron density gradients are responsible for the enhanced radar echoes, (2) energetic particles are not part of the spread F phenomena, (3) wave measurements are strongly correlated with the Doppler character of the radar signals, and (4) there is a one-to-one correspondence of the largescale irregularities responsible for scintillations of satellite radio transmissions and ionosonde spread echoes with the small-scale irregularities responsible for the backscatter of VHF radar signals. We present and discuss the implications of the data. A general description of the phenomena and theories attempting to explain spread F, circa 1970, has been given by Farley et al. [1970]. The irregularities which cause the spread ionograms and radio scintillations occur at all heights in the F region and can be observed with the Jicamarca incoherent backscatter radar at all altitudes up to 1200 km. Recently, a number of new and possibly related phenomena have been observed, including intense soft particle fluxes [Heikkila, 1971], strong VLF emissions [Laaspere and Semprebon, 1974], enhanced optical emissions [Leoasseur and Blamont, 1973; Meier and Weller, 1975], and abnormal ion composition and flow [Hanson and Sanatani , 1971]. These observations led to a desire to simultaneously measure the vertical profile well into the topside ionosphere of energetic particles, ion composition, the electric and magnetic field components, atmospheric emissions, and the critically important electron density fluctuations. A crucial part of this experiment was to couple these in situ measurements with simultaneous ground-based measurements of scintillations, Jicamarca radar backscattered power and spectra, ionosonde reflections, and optical emissions.Coupling of these techniques provides the data necessary to determine whether the 3-m irregularities detected by the radar are related to the large-scale irregularities observed with ionosondes and scintillations. From these data we also anticipated being able to determine the interrelationships, if any, betweenThe ground-based data reported in this paper were obtained from several installations which together with the equipment utilized are shown in Table 1. The locations of these sites are shown in Figure 1. The launch site permits rockets to be launched along the magnetic field lines or equatorial electrojet. The Anc6n, Huancayo, and Jicamarca observatories were operated by personnel of the Instituto Geofisico del Peru. The range was operated under the authority of the Peruvian government by the instituto and experimental personnel. A nc6n Obseroatory The Anc6n Observa...

Measurements of the velocity dependence of the angular intensity distribution of potassium and cesium beams scattered by a crossed beam of mercury are presented. The alkali beam was velocity selected, with a triangular velocity distribution (half-intensity width 4.7% of peak velocity); the velocity was varied over the range 185-1000 m/sec. The Hg beam had a thermal distribution; the average Hg speed was ~235 meters per second. The scattering data have been converted to the center-of-mass system. The angular distributions show the expected strong forward scattering and evidence the phenomenon of rainbow scattering. The energy dependence of the rainbow angle is used to evaluate the interatomic potential well depth, interpreted as the dissociation energy D, of the 22;+ molecular ground state. Values (in ergX 10 14 ) thus obtained (±5%) are 7.46 for KHg and 7.72 for CsHg. Absolute values of differential cross sections could not be obtained; only relative cross sections D(O) are reported. The observed low-angle behavior D(O) a:.O-713 serves as direct experimental confirmation of the ,-6 dependence of the long-range attractive potential for K-Hg and Cs-Hg systems.

Three simple photodiodes on the Spades satellite (1968-059A) have measured the nearearth solar flux in three broad wavelength intervals: 300-1150 A, 1150-1600 A, and 1600-2100 A. During the first 27 days of the satellite's lifetime, the signals in the two longer wavelength intervals showed nonrandom variations of more than 50% from the mean, and the short wavelength flux varied by 40%. Except for the 1150-1600 A channel, the variation did not correlate well with Fxo.•; all three channels showed a much stronger correlation with the area times intensity of calcium plage regions. The data are consistent with a model in which the effective plage temperature is about 1250øK higher than the background sun at all wavelengths in the 300-2100 A interval.

Vacuum-ultraviolet absorption measurements of the resonance lines of O, N, and H by the line-absorption method are described. They lend further support to the correctness of the gas-titration reactions of O and N by NO2 and NO. Line-shape difficulties are reduced by means of an optically thin light source. Based on a simple Doppler emission—Doppler absorption model, oscillator strengths, Σgf, of 0.3±0.1 are obtained for the oxygen-resonance triplet near 1300 Å, and lower limits of 0.2 and 0.6 for the nitrogen triplet near 1200 Å and the Lyman alpha doublet. Preliminary experiments on the detection of metastable excited states of O and N are also described.

Primary electron fluxes, measured by two satellites as they crossed quiet time (Kp = 1, Σ Kp = 11+) auroral arcs, are presented for times near 1420 UT on November 12, 1972. The DMSP 30 satellite measured the optical intensity at 0.6–1.0 µm full width at half maximum (FWHM) and precipitated electrons with 0.22 ≤ E ≤ 19.7 keV near 2100 MLT. The 72‐1 satellite crossed the auroral arc system near 2200 MLT and measured 0.36‐ to 16.5‐keV electrons at all pitch angles. A detailed description of the electron morphology that includes comparisons of electron fluxes with optical intensities is presented. We find that the optical intensities extending from 2100 to 2200 MLT correlate best with electrons with E > 1 keV. The strongest emission bands at these near‐infrared wavelengths are N2(IP) (first‐positive band of N2) and N2+(M) (Meinel band of N2+). We estimate that between 4 and 10% of the primary electron energy input is converted to an optical intensity of 140 kR between 0.6 and 1.0 µm FWHM and is equivalent to a weak IBC 2 in the 5577‐Å green line of atomic oxygen.