Ionospheric precursors observed at low latitudes around the time of koyna earthquake

On December 11, 1967 at 05:21 LT, an immense earthquake of magnitude 6.7 struck Koyna, the Indian province of Maharashtra. Its epicenter was located at geographic latitude 17.37°N and longitude 73.75°E with depth of about 3 km. Ground based measurements show variation in the critical frequency of ionospheric F2 layer (foF2) before and after the shock. In the present study the behavior of F2-region of ionosphere has been examined over the equatorial and low latitudinal region ionosphere during the month of December 1967 around the time of Koyna earthquake. For this purpose, the ionospheric data collected with the help of ground-based ionosondes installed at Hyderabad (located close to the earthquake epicenter) Ahmedabad, Trichirapulli, Kodaikanal and Trivendrum have been utilized. The upper and lower bound of Interquartile range (IRQ) are constructed to monitor the variations in foF2 other than day-to-day and diurnal pattern for finding the seismo-ionospheric precursors. Some anomalous electron density variations are observed between post midnight hours to local pre-noon hours at each station. These anomalies are strongly time dependent and appeared a couple of days before the main shock. The period considered in this study comes under the quiet geomagnetic conditions. Hence, the observed anomalies (which are more than the usual day-to-day variability) over all stations are likely to be associated with this imminent earthquake. The possible mechanism to explain these anomalies is the effect of seismogenic electric field generated just above the surface of earth within the earthquake preparation zone well before the earthquake due to emission of radioactive particles and then propagated upward, which perturbs the F-region ionosphere.     

Temperature effects in the ATIC BGO calorimeter

The Advanced Thin Ionization Calorimeter (ATIC) Balloon Experiment had a successful test flight and a science flight in 2000–01 and 2002–03 and an unsuccessful launch in 2005–06 from McMurdo, Antarctica, returning 16 and 19 days of flight data. ATIC is designed to measure the spectra of cosmic rays (protons to iron). The instrument is composed of a Silicon matrix detector followed by a carbon target interleaved with scintillator tracking layers and a segmented BGO calorimeter composed of 320 individual crystals totaling 18 radiation lengths to determine the particle energy. BGO (Bismuth Germanate) is an inorganic scintillation crystal and its light output depends not only on the energy deposited by particles but also on the temperature of the crystal. The temperature of balloon instruments during flight is not constant due to sun angle variations as well as differences in albedo from the ground. The change in output for a given energy deposit in the crystals in response to temperature variations was determined.     

Real-time GLE alert in the ANMODAP Center for December 13, 2006

Within the last years, a real-time system to monitor high energy cosmic rays for space weather use has been operated at Athens cosmic ray station. Neutron monitors and satellite high resolution data in real time are used, making it possible to observe cosmic rays in dual energy range observations. In large solar energetic particle (SEP) events, ground level enhancement (GLE) can provide the earliest alert for the onset of the SEP event. This system watches for count rate increases recorded in real time by 23 neutron monitors, which triggers an alarm if a ground level enhancement (GLE) of cosmic ray intensity is detected.     

Magnetospheric electric field variations caused by storm-time shock fronts

On January 20, 2005 there was an X 7.1 solar flare at 0636 UT with an accompanied halo coronal mass ejection (CME). The resultant interplanetary shock impacted earth ∼36 h later. Near earth, the Advanced Composition Explorer (ACE) spacecraft observed two impulses with a staircase structure in density and pressure. The estimated earth-arrival times of these impulses were 1713 UT and 1845 UT on January 21, 2005. Three MINIature Spectrometer (MINIS) balloons were aloft on January 21st; one in the northern polar stratosphere and two in the southern polar stratosphere. MeV relativistic electron precipitation (REP) observed by all three balloons is coincident (<3 min) with the impulse arrivals and magnetospheric compression observed by both GOES 10 and 12. Balloon electric field data from the southern hemisphere show no signs of the impulse electric field directly reaching the ionosphere. Enhancement of the balloon-observed convection electric field by as much as 40 mV/m in less than 20 min during this time period is consistent with typical substorm growth. Precipitation-induced ionospheric conductivity enhancements are suggested to be (a) the result of both shock arrival and substorm activity and (b) the cause of rapid (<6 min) decreases in the observed electric field (by as much as 40 mV/m). There is poor agreement between peak cross polar cap potential in the northern hemisphere calculated from Super Dual Auroral Radar Network (SuperDARN) echoes and horizontal electric field at the MINIS balloon locations in the southern hemisphere. Possible reasons for this poor agreement include (a) a true lack of north–south conjugacy between measurement sites, (b) an invalid comparison between global (SuperDARN radar) and local (MINIS balloon) measurements and/or (c) radar absorption resulting from precipitation-induced D-region ionosphere density enhancements.     

Enhancing the ATIC charge resolution

The Advanced Thin Ionization Calorimeter (ATIC) experiment is designed to investigate the charge composition and energy spectra of primary cosmic rays over the energy range from about 10¹¹ to 10¹⁴ eV during Long Duration Balloon (LDB) flights from McMurdo, Antarctica. Currently, analysis from the ATIC-1 test flight and ATIC-2 science flight is underway and preparation for a second science flight is in progress. Charge identification of the incident cosmic ray is accomplished, primarily, by a pixilated Silicon Matrix detector located at the very top of the instrument. While it has been shown that the Silicon Matrix detector provides good charge identification even in the presence of electromagnetic shower backscatter from the calorimeter, the detector only measures the charge once. In this paper, we examine use of the top scintillator hodoscope detector to provide a second measure of the cosmic ray charge and, thus, improve the ATIC charge identification.     

CREAM: 70 days of flight from 2 launches in Antarctica

The Cosmic-Ray Energetics And Mass balloon-borne experiment has been launched twice in Antarctica, first in December 2004 and again in December 2005. It circumnavigated the South Pole three times during the first flight, which set a flight duration record of 42 days. A cumulative duration of 70 days within 13 months was achieved when the second flight completed 28 days during two circumnavigations of the Pole on 13 January 2006. Both the science instrument and support systems functioned extremely well, and a total 117 GB of data including 67 million science events were collected during these two flights. Preliminary analysis indicates that the data extend well above 100 TeV and follow reasonable power laws. The payload recovered from the first flight has been refurbished for the third flight in 2007, whereas the payload from the second flight is being refurbished to be ready for the fourth flight in 2008. Each flight will extend the reach of precise cosmic-ray composition measurements to energies not previously possible.     

Gamma-ray detector on board lunar mission Chang’E-1

Gamma-ray spectrometer (GRS) is included in the payload of Chinese first lunar mission Chang’E-1 that will be launched in 2007. Specific objectives of the GRS are to map abundance of O, Si, Fe, Ti, U, Th, K, and perhaps, Mg, Al, and Ca to depths of about 20 cm. There are remarkable advantages for GRS application to remote sensing elemental materials over the entire lunar surface: large effective area and good ability for background rejection. We will describe the design of GRS and present its performance in this paper. Moreover, the GRS calibration will also be introduced.     

Signs of hypothetical flora on the planet venus: Revision of the TV experiment data (1975–1982)

Unique archive data from investigations of the surface of Venus performed with television cameras on the VENERA missions in 1975 and 1982 were reprocessed with up-to-date techniques, which substantially improved their level of detail. Numerous objects exhibiting a complex regular structure and presumably very slow motions (in the case of hypothetical fauna) have been found. The objects are noticeable in size and may testify to the existence of life. This paper reviews the results of searching for and identifying hypothetical objects of Venusian flora. The detected and identified hypothetical objects considerably exhaust the corresponding potential of the television images. It is concluded that, to investigate the surface of Venus, a new special mission, much more sophisticated than the VENERA missions (1975–1982), should be urgently carried out.