Rocket Range Research Articles

Plasma density over Svalbard during the ISBJØRN campaign

Abstract. In 1997, reliable operation of the EISCAT Svalbard Radar (ESR) was achieved and a rocket launching facility at Ny Ålesund on Svalbard (79°N, 12°E) (SVALRAK) was established. On 20 November, 1977, the first instrumented payload was launched from SVALRAK. Although the payload configuration had been flown many times previously from Andøya Rocket Range on the Norwegian mainland, this presented an unprecedented in situ determination of positive ion density over Svalbard. Simultaneously, ESR measured similar density profiles but in a higher altitude regime. We have combined the ESR measurements with ionosonde data to establish a calibration and subsequently combined the ground-based and in situ determined profiles to give a composite positive ion density profile from the mesosphere to the thermosphere.Key words: Ionosphere (polar ionosphere; instruments and techniques)

Irregular structures observed below 71 km in the night-time polar D-region

Abstract. A new rocket range, SvalRak, was opened in November 1997 at Ny-Ålesund (79°N) in the Svalbard archipelago. The first instrumented rocket was launched on 20 November, 1997, at 1730 UT during geomagnetically quiet conditions. The payload was instrumented to measure plasma parameters in the mesosphere and lower thermosphere, but the payload only reached an altitude of 71 km. This resulted in a very flat trajectory through the lower D-region. The positive ion concentrations were larger than expected, and some unexpected plasma irregularities were observed below 71 km. The irregularities were typically 100 m in spatial extent, with plasma densities a factor of two to five above the ambient background. In the dark polar night the plasma below 71 km must consist mainly of positive and negative ions and the only conceivable ionising radiation is a flux of energetic particles. Furthermore only relativistic electrons have the large energies and the small gyro radii required in order to explain the observed spatial structure. The source of these electrons is uncertain. Key words: Ionosphere (ionospheric irregularities; ionization mechanisms) - Magnetospheric physics (polar cap phenomena)

Features of lower ionosphere during day and night over magnetic equator

Rocketborne measurements of ionospheric parameters over magnetic equator Thumba, India are presented in this paper. Results obtained from another rocket range, SHAR, India situated off the equator are also presented. The production mechanism of plasma irregularities in 80–150 km altitude in various scale sizes are discussed. Similarities and differences in various kind of plasma processes like gradient drift instability, two stream instability and wind induced effects at both the locations are discussed.

MASERATI: a rocketborne tunable diode laser absorption spectrometer

The MASERATI (middle-atmosphere spectrometric experiment on rockets for analysis of trace-gas influences) instrument is, to our knowledge, the first rocket-borne tunable diode laser absorption spectrometer that was developed for in situ measurements of trace gases in the middle atmosphere. Infrared absorption spectroscopy with lead salt diode lasers is applied to measure water vapor and carbon dioxide in the altitude range from 50 to 90 km and 120 km, respectively. The laser beams are directed into an open multiple-pass absorption setup (total path length 31.7 m) that is mounted on top of a sounding rocket and that is directly exposed to ambient air. The two species are sampled alternately with a sampling time of 7.37 ms, each corresponding to an altitude resolution of approximately 15 m. Frequency-modulation and lock-in techniques are used to achieve high sensitivity. Tests in the laboratory have shown that the instrument is capable of detecting a very small relative absorbance of 10(-4)-10(-5) when integrating spectra for 1 s. The instrument is designed and qualified to resist the mechanical stress occurring during the start of a sounding rocket and to be operational during the cruising phase of the flight when accelerations are very small. Two almost identical versions of the MASERATI instrument were built and were launched on sounding rockets from the Andøya Rocket Range (69 degrees N) in northern Norway on 12 October 1997 and on 31 January 1998. The good technical performance of the instruments during these flights has demonstrated that MASERATI is indeed a new suitable tool to perform rocket-borne in situ measurements in the upper atmosphere.

First simultaneous in situ measurement of electron density and electric field fluctuations during spread F in the Indian Zone

The paper presents results of in situ measurements of electron density and electric field fluctuations (δne, δE'v and δE'H) during a strong spread F event from the SHAR rocket range in India. Intermediate scale ne irregularities were observed in the F region valley over SHAR, which was earlier found to be free from irregularities. Experimental evidence of the validity of the image striation theory is provided through first simultaneous spectral measurement of electron density and electric field in the valley region. Correlation analysis of δne, δE'v and δE'H suggests the existence of a sheared flow of current below the F‐peak. A new type of irregularity in the intermediate scale having a steep spectrum (n = −3.1) has also been detected in the valley region. A very sharp layer of ionization wherein the electron density increased by a factor of 50 in 10 km vertical extent was detected at 105 km.

The SEEK (Sporadic‐E Experiment over Kyushu) Campaign

The SEEK (Sporadic‐E Experiment over Kyushu) campaign was conducted in late August 1996 from the southern region of Kyushu, Japan, to investigate the mechanism for the generation of quasi‐periodic (QP) radar backscatter from field‐aligned irregularities imbedded in nighttime sporadic‐E (Es) layers. SEEK was designed to determine in‐situ small‐scale electrodynamical properties using two sounding rockets and large‐scale dynamics and electrodynamics using ground‐based sensors, which included a transportable radar and other radio and optical instruments deployed in the vicinity of the rocket range. It was observed by this campaign that Es layers existed in a convergent wind shear region, where large electric fields were induced and when active atmospheric gravity waves existed in the mesosphere. However, there was little evidence which positively supported the hypothesis that Es layers were deeply modulated in altitude.

Simultaneous measurements of X-rays and electrons during a pulsating aurora

Abstract. The PULSAUR II rocket was launched from Andøya Rocket Range at 23.43 UT on 9 February 1994 into a pulsating aurora. In this paper we focus on the observations of precipitating electrons and auroral X-rays. By using models it is possible to deduce the electron energy spectrum from X-ray measurements. Comparisons are made between the deduced electron fluxes and the directly measured electron fluxes on the rocket. We found the shape of the observed and the deduced electron spectra to fit very well, with almost identical e-folding energies in the energy range from 10 ke V to ~60–80 ke V. For the integrated fluxes from 10.8 to 250 ke V, we found a discrepancy of 30% . By combining two models, we have found a good method of deducing the electron precipitation from X-ray measurements. The discrepancies between calculations and measurements are in the range of the uncertainties in the measurements.Key words. Ionospheric particle precipitation · Magnetospheric physics · Annual phenomena · Energetic particle

Detection of a meteor contrail and meteoric dust in the Earth's upper mesosphere

In 1983 a series of small rockets were launched from the Poker Flat Rocket Range near Fairbanks, Alaska to study what has come to be called Polar Mesospheric Summer Echoes (PMSE). We report here on a fortuitous simultaneous 50-MHz radar and rocket detection of what seems to be a meteor contrail produced over the Poker Flat Rocket Range. The two data sets are mutually consistent and taken together suggest some very interesting properties for the trails of large meteors. Most notable is the first evidence that the ablated material can coagulate into particles the order of 50 nm in radius. This estimate is based primarily on the fall speed deduced from both the Doppler shift of the VHG radar signal and the time rate of change of the target as it fell through the beam. In addition the very existence of the radar target, the extremely sharp edges of the trail, and the existence of electron density structures inside the trail more than an order of magnitude smaller than the Kolmogorov microscale, all require large charged aerosols and a very high Schmidt number. Curiously the environment leading to PMSE (the study of which was our primary mission), is very similar to the properties of a large meteor trail some minutes after it is formed. In the PMSE case ice particles grow and become charged by the plasma and, when more than half the charge is tied up on the ice, the plasma diffusion coefficient becomes so small that structure can be supported at VHF scattering scales. In the late-time meteor case large aerosols coagulate and tie up both natural charge in the plasma and the original meteor trail electrons, Following the work of Rosinski and Snow (1961) and Hunten et al. (1980) we conclude that the incident meteor was the order of 100 g and would have had a visual magnitude of about - 5. This dust production process may resolve some open questions concerning long-lived meteor radar echoes. For example, in the event studied the electron density was well into the underdense condition and yet was detected for over 6 min. Classical meteor scatter theory has no explanation for such a long duration underdense event. c 1998 Elsevier Science Ltd. All rights reserved

Simultaneous measurements of X-rays and electrons during a pulsating aurora

The PULSAUR II rocket was launched from Andøya Rocket Range at 23.43 UT on 9 February 1994 into a pulsating aurora. In this paper we focus on the observations of precipitating electrons and auroral X-rays. By using models it is possible to deduce the electron energy spectrum from X-ray measurements. Comparisons are made between the deduced electron fluxes and the directly measured electron fluxes on the rocket. We found the shape of the observed and the deduced electron spectra to fit very well, with almost identical e-folding energies in the energy range from 10 ke V to ~60–80 ke V. For the integrated fluxes from 10.8 to 250 ke V, we found a discrepancy of 30% . By combining two models, we have found a good method of deducing the electron precipitation from X-ray measurements. The discrepancies between calculations and measurements are in the range of the uncertainties in the measurements.Key words. Ionospheric particle precipitation · Magnetospheric physics · Annual phenomena · Energetic particle

First results from the energetic particle instrument on the OEDIPUS-C sounding rocket

The Canadian / US OEDIPUS-C rocket was flown form the Poker Flat Rocket Range November 6th 1995 as a mother-son sounding rocket. It was designed to study auroral ionospheric plasma physics using active wave sounding and prove tether technology. The payload separated into two sections reaching a separation of 1200m along the Earth's magnetic field. One section included a frequency stepped HF transmitter and the other included a synchronised HF receiver. Both sections included Energetic Particle Instruments, EPI, stepped in energy synchronously with the transmitter steps. On-board EPI particle processing in both payloads provided direct measurements of electron heating, wave-particle interactions via particle correlators, and a high resolution measurement of wave induced particle heating via transmitter synchronised fast sampling. Strong electron heating was observed at times when the HF transmitter frequency was equal to a harmonic of the electron gyrofrequency, f ce, or equal to the upper hybrid frequency, f uh.

Seasonal variation of turbulent energy dissipation rates at high latitudes as determined by in situ measurements of neutral density fluctuations

In the last 6 years a series of 22 sounding rockets were launched in order to investigate the dynamic state of the mesosphere and lower thermosphere. Of these flights, 19 were performed at high latitudes, either from the Andøya Rocket Range (17 flights) in northern Norway (69°N) or from Esrange (2 flights) in northern Sweden (68°N). An ionization gauge mounted on board these sounding rockets measured neutral density fluctuations down to very small spatial scales of a few meters. During several flights, small‐scale density fluctuations were found in layers of a few kilometers thickness. Subsequent analysis of these fluctuations indicates that they were caused by turbulent motions. The high resolution of these measurements makes it possible to unambiguously deduce turbulent energy dissipation rates ε from the spectra of the relative density fluctuations. The ε profiles and the corresponding heating rates obtained at high latitudes show a significant and systematic seasonal variation: Whereas in winter the turbulent heating rates are comparatively small (typically 0.1 K/d and 1–2 K/d below and above ∼75 km, respectively) in the entire mesosphere and lower thermosphere, much stronger mean values of ∼10–20 K/d are observed around the summer mesopause (∼90 km). During none of the seven summer flights have we detected any noticeable turbulence in the middle and lower mesosphere. Turbulence is confined to a relatively small height region of 78–97 km during summer but covers the entire mesosphere from 60 to 100 km during winter. From our measurements we arrive at the curious conclusion that turbulent heating in the mesosphere is strongest at the coldest part of the atmosphere, namely, at the polar mesopause in summer. Our observations imply that turbulent heating is an important contribution to the energy budget of the upper mesosphere in summer, whereas it is presumably negligible in the entire mesosphere in winter. Mean turbulent velocities wturb and mean turbulent diffusion coefficients K do not exhibit such a distinct seasonal variation. In the lower and upper mesosphere, typical values for wturb are 0.3 and 1–3 m/s, respectively, and typical values for K are 4 and 100 m2/s, respectively. The seasonal variation of mean profiles of turbulent parameters as obtained by high‐resolution in situ techniques puts a serious constraint on models dealing with the energy budget of the upper atmosphere, in particular the parameterization of subgrid process in terms of mean state quantities, e.g., used in gravity wave breaking scenarios.

Chlorine and bromine ions in the D-region

In the first D-region negative ion measurements of March 7, 1970 above Wallops Island by Narcisi's group at the Geophysical Laboratory in Bedford no chlorine ions were reported. However, already in the second measurement from the Andoya rocket range on March 23, 1970, by Arnold's group at Heidelberg the presence of the two chlorine ion isotopes 35 and 37 amu/q were found as minor ions of the D-region. Since then the negative chlorine ion was observed regularly in the D-region negative ion population, but its chemistry is still not fully understood. In a solar eclipse campaign in February 1979 the ion composition was measured with a new mass spectrometer by the Bern group. In this measurement Cl − was the most abundant ion below about 70 km. In addition, good evidence was found for the presence of both bromine isotopes 79 and 81 amu/q and also of clustered chlorine ions. Since the source of chlorine and bromine ions is the stratosphere, time-dependant changes of these compounds will also contribute to a change of chlorine and bromine negative ions in the D-region. Both ions play an important role in the ion population of the D-region, a fact which is not taken into account by today's standard models.

Experimental evidence for unstable waves in the lower E/Upper D‐region excited near the bisector between the electric field and the drift velocity

During the METAL campaign conducted at Andøya Rocket Range in September–October 1991, detailed in situ measurements were performed by means of plasma probes in the TURBO rocket payload. During one of the salvoes (30 September 1991), strong plasma density fluctuations were detected above 78 km, especially on downleg. The results are shown to be in good agreement with the new instability predicted from the kinetic theory of Dimant and Sudan (1995). The new instability leads to the excitation of long wavelength plasma waves along the bisector between the drift velocity Vd and the electric field E.

First detection of charged dust particles in the Earth's mesosphere

Some theories for the observed anomalous radar backscatter during the summer (polar mesospheric summer echoes, or PMSE) and electron bite outs measured by rockets require the presence of charged dust. To investigate this, two dust probes have been launched in 1994 from Andøya Rocket Range and we here report the results from the dust and an electron probe on the two payloads. The dust probes were designed to block out the electron and ion components at the mesopause but to detect primary currents due to impacts of charged dust and also to detect secondary plasma production during dust impacts. The results indicate that both during PMSE and noctilucent cloud (NLC) conditions, large amounts of dust, with average sizes apparently of about 0.1 μm and less, were present. The number densities Nd can be up to many thousand per cubic centimeter, and the charge density NdZd likewise. Large local gradients in density and charge density of dust are detected. Dust carrying both positive and negative charges can apparently be present on different occasions. In some parts of the NLC/PMSE layers we find that the negative charge density locked in grains is so large that the number of free electrons is significantly reduced there because the dust acts like sinks for electrons, and an electron bite out results. We also find that in one case the presence of positive dust leads to an increase in the local electron density by photoionization. The main uncertainties in the data analysis are the structure of the dust and the secondary plasma production at the comparatively low dust impact velocities (1 km s−1) in the experiment.

Atomic War, Empire Strategic Dispersal and the Origins of the Snowy Mountains Scheme

(1996). Atomic War, Empire Strategic Dispersal and the Origins of the Snowy Mountains Scheme. War & Society: Vol. 14, No. 1, pp. 121-144.

Noctilucent clouds and the thermal structure near the Arctic mesopause in summer

In the summers of 1993 and 1994 a series of meteorological rockets and sounding rockets were launched from the Andøya Rocket Range (69°N) during the SCALE and ECHO campaigns in order to investigate the state of the mesosphere and lower thermosphere (SCALE = “SCAttering Layer Experiment”; ECHO indicates that radar and lidar echoes are investigated). At the same location a Rayleigh lidar was operational during these campaigns and searched for enhanced backscatter signals from the upper mesosphere indicative of the presence of noctilucent clouds (NLC). In five cases the lidar detected a NLC and the atmospheric temperature profile was obtained simultaneously by in situ techniques. A literature survey shows that there are only three more cases of unambiguous and simultaneous observations of NLC temperature and altitude. The temperature profiles obtained during SCALE and ECHO are as expected for the high‐latitude summer season: The mean mesopause temperature is 135 K at an altitude of 87.5 km. The variability of the temperatures is smaller above ∼84 km altitude than below. The mean temperature below the mesopause shows a remarkable repeatability ever since the first measurements 30 years ago; at the lower edge of the NLC heights (82 km) it is again and again observed to be in the range 150 ± 2 K and the variability within each data set is only a few Kelvins. Such an “equithermal submesopause” in summer puts a serious constraint on any model prediction of secular changes of temperatures in the upper mesosphere. The mean altitude of the NLCs as determined from our lidar measurements is 83.1 km which is surprisingly close to the very first height determinations more than 100 years ago. It is conceivable that this repeatability in altitude reflects a similar repeatability of the thermal structure. There is no apparent correlation between the conditions at the mesopause and the occurrence of NLCs at lower altitudes. The physical reason behind this is presumably related to the fact that the wind direction changes at ∼87 km height, which implies that the air masses observed above the rocket site near mesopause altitudes have been advected from different locations than those at NLC heights. The NLCs are always located below the mesopause, and the temperature in the NLC layer is observed to be lower than 154 K. Our results are compatible with the idea that NLCs consist of ice particles which start to nucleate around the mesopause, sediment to lower altitudes while growing, become observable by the lidar and/or by the naked eye, and finally evaporate once they approach the higher temperatures around 82 km.

Rayleigh lidar detection of aerosol echoes from noctilucent cloud altitudes at the Arctic Circle

During 3 out of 16 observations runs in July and August 1993 the Rayleigh Lidar at the Andøya Rocket Range (69°N, 16°E) in Northern Norway detected aerosol echoes from noctilucent cloud altitudes on July 28, August 7, and August 9. The geometric elevation of the center of the Sun was from +1.3° to −4.5° during aerosol detection. These three events differed significantly in peak signal strength, altitude, cloud layer shape, altitude integrated signal, and temporal evolution. Aerosol echoes were seen from the altitude range 81 to 87 km. The strongest aerosol event showed a peak backscatter ratio of 240 at 83.2 km altitude equivalent to the molecular (Rayleigh) scattering signal from 41.5 km. The weakest event had a peak backscatter ratio of 7 at 84.8 km with a Rayleigh equivalent altitude of 73.3 km. The zenith optical thickness of the aerosol layers varied by approximately two orders of magnitude. Detection times ranged from longer than 5 hours to as short as 15 minutes. The temporal evolution during the events suggests that single clouds were drifting through the laser beam which has a diameter of approximately 4 m at 85 km altitude. All events occurred before local midnight and the gross temporal evolution is compatible with tidal models for the diurnal variation of the visibility in PMCs and NLCs although there is considerably more structure in the lidar data than predictable by such a model. The estimated zenith optical thickness is within the bounds of microphysical NLC models.

PAMS chosen for CNC programming

The maiden flight of the Eurofighter 2000 combat aircraft in March 1994 was a significant milestone for the many companies contracted to supply components for its build. Among them was ML Aviation, which manufactures weapons carriage and release systems as well as a range of nasal and aircraft rocket and decoy flare systems.

Plasma instabilities in the lower E-region observed during the DYANA campaign

During the DYANA campaign a number of instrumented sounding rockets were launched from Andøya Rocket Range (ARR) in Norway (69°N) to study the dynamics of the mesosphere and lower thermosphere during winter conditions. The EISCAT UHF radar in Tromsø, located 130 km to the east of ARR, was used to map the electric field and the wind field in the same height region. During some of the launches, plasma irregularities with scales in the range from a few metres to tens of metres were observed. We focus our attention on an event which took place on 8/9 March 1990. Two instrumented payloads code-named DAT-73 and DAT-76 were flown 92 min apart during different levels of disturbance in the E-region. We have studied the plasma fluctuations observed during these flights in terms of the modified two-stream and gradient-drift instabilities using linear fluid theory. The observed height extent of the disturbed region is in excellent agreement with theoretical predictions based upon measurements of background plasma parameters. We also find that the instability is much stronger during the first part of the event as a consequence of larger drift velocities. This is evident by the large plasma fluctuations measured in situ as well as the electron temperature measured by EISCAT. An adequate description of the observations must include effects of electron density gradients and recombinational damping. During the flight of DAT-73, the plasma waves must propagate in a direction different from 90° with respect to the magnetic field, while the DAT-76 observations can be explained by plasma waves propagating normal to the magnetic field.

First simultaneous measurements of neutral and ionized iron densities in the upper mesosphere

We report on the results of a multi‐instrument study of a sporadic Fe layer and a sporadic E layer which took place in the night of September 20, 1991, at the Andøya Rocket Range (69°N, 16°E). A ground‐based lidar was used to measure mesospheric Fe densities, while simultaneously rocket‐borne probes and an ion mass spectrometer measured the profile of total ion density and ion composition, respectively. All instruments observed the sporadic layers near 97 km altitude. Radar tracking of chaff clouds established the wind field in the 90‐ to 100‐km region with high spatial resolution, while the EISCAT incoherent scatter radar measured the E fields in the F region. The major ion in the sporadic E layer turned out to be Mg+. The narrow Fe+ layer was 1 km lower than the sporadic Fe+ layer. The ratio of densities [Fe+]/[Fe] in the peaks of the sporadic layers was found to be 1.75.