Detailed analysis of dynamic evolution of three Active Regions at the photospheric level before flare and CME occurrence

We present a combined analysis of the applications of the weighted horizontal magnetic gradient (denoted as ${\mathit{WG}}_M$ in Korsós et al. (2015)) method and the magnetic helicity tool (Berger and Field, 1984) employed for three active regions (ARs), namely NOAA AR 11261, AR 11283 and AR 11429. We analysed the time series of photospheric data from the Solar Dynamics Observatory taken between August 2011 and March 2012. During this period the three ARs produced a series of flares (eight M- and six X-class) and coronal mass ejections (CMEs). AR 11261 had four M-class flares and one of them was accompanied by a fast CME. AR 11283 had similar activities with two M- and two X-class flares, but only with a slow CME. Finally, AR 11429 was the most powerful of the three ARs as it hosted five compact and large solar flare and CME eruptions. For applying the ${\mathit{WG}}_M$ method we employed the Debrecen sunspot data catalogue, and, for estimating the magnetic helicity at photospheric level we used the Space-weather HMI Active Region Patches (SHARP’s) vector magnetograms from SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager). We followed the evolution of the components of the ${\mathit{WG}}_M$ and the magnetic helicity before the flare and CME occurrences. We found a unique and mutually shared behaviour, called the U-shaped pattern, of the weighted distance component of ${\mathit{WG}}_M$ and of the shearing component of the helicity flux before the flare and CME eruptions. This common pattern is associated with the decreasing-receding phases yet reported only known to be a necessary feature prior to solar flare eruption(s) but found now at the same time in the evolution of the shearing helicity flux. This result leads to the conclusions that (i) the shearing motion of photospheric magnetic field may be a key driver for solar eruption in addition to the flux emerging process, and that (ii) the found decreasing-approaching pattern in the evolution of shearing helicity flux may be another precursor indicator for improving the forecasting of solar eruptions.     

一种提高动态温度测量精度的方法

在信号分析的基础上,提出了在频域内对传感器测量值进行动态修正,改善传感器的动态特性,提高动态温度测量精度的方法。用于热敏电阻测温时,能显著改善动态特性和测温精度,其响应速度可提高6～7倍。     

8"×8" full color cockpit display

The operation of active matrix liquid crystal displays (AMLCDs), the preferred flat-panel displays for avionic and aerospace applications, is explained. An 8-in.×8-in. full-color AMLCD designed for a military aircraft is described, as well as the principles of the p-i-n diode switch on which its design is based. The performance characteristics of the display are examined     

Optimal Utilization of Satellite Communication Systems through Supervisory Control

Users of satellite communication systems being designed are charcterized by diversity. System designers now have the capability of serving thousands of simultaneous users; the users need not all follow the same system parameters. Diversity and characteristics are shown, and an attempt is made to list all the parameters desired by users. Usage of satellite communications systems is projected to serve a maximum of 200 000 users by means of 10 multipurpose satellites. It is shown that a supervisory control system is necessary to achieve optimal utilization of the existing resources.     

Monopulse Radar Angle Tracking Accuracy with Sum Channel Limiting

The variance of angle tracking error is found for an amplitude-comparison form of monopulse radar when the sum channel contains a limiter prior to the angle error detector. The error expression is valid for any shape of transmitted pulse and any duration of range tracking gate but does assume matched filters in signal processing channels. The procedures used are rigorous and an example of results is worked out for the special case of a rectangular transmitted pulse envelope. It is shown, for rectangular pulses, that achievable angle tracking error variance with sum channel limiting is not more than 2.22 dB larger than the theoretical minimum for any processor and not more than 1.29 dB larger than a similar signal processor that uses a "linear" angle error detector. Results apply for large single-pulse signal-to-noise ratio.     

An extraterrestrial habitat on Earth: the algal mat of Don Juan [correction of Jaun] Pond.

On the edge of Don Juan Pond in the Wright Valley of Antarctica lies a mat of mineral and detritus cemented by organic matter. In spite of a CaCl2 concentration of about 33% (w/v), the mat contains Oscillatoria and other cyanobacteria, unicellular forms, colonial forms rich in carotenoids, and diatoms. Bacteria are rare; fungal filaments are not. Oscillatoria showed motility but only at temperatures <10 degrees C. Acetone extracts of the mat and nearby muds yielded visible spectra similar to those of laboratory grown O. sancta, with 50- to 70-fold molar ratio of chlorophyll a to b. Although rare, tardigrades were also found. The algal mat had enzymatic activities characteristic of peroxidase, catalase, dehydrogenase, and amylase. Cellulose, chitin, protein, lipid and ATP were present. Previously, algae in the Wright Valley have been described in melt water, not in the brine itself. Wright Valley has been used as a near sterile Martian model. It obviously contains an array of hardy terrestrial organisms.     

Multipath Angle Error Reduction Using Multiple-Target Methods

The usual methods of reducing multipath angle errors in monopulse tracking radar achieve only limited success because they do not attack the root of the problem. A more correct approach is to accept the multipath signal as a second target and utilize a two-target signal processor which angle tracks both wavefronts. The processor will decouple the return signals so that relatively interference-free data on both waves are obtained. In this paper a signal processor for separating signal from (N - 1) multipath components is developed. The processor is then specialized to the case of only one multipath signal and evaluated by a computer simulation. Data show that large improvements are possible as compared to the usual monopulse tracking system. In particular, the usual large bias errors at low elevation angles are eliminated. Tracking precision compares favorably with the theoretically best possible for two-target tracking systems.     

Artifical plasma jet in the ionosphere

The PORCUPINE sounding rocket project provided the opportunity to study the dynamics of an artificially injected plasma beam in the near-Earth space. The structure of the plasma beam, its propagation across the magnetic field as well as the resulting wave phenomena will be discussed.     

Peculiarities of the environment disturbance during the electron beam injection from the rocket

The paper presents some results obtained when a beam of electrons (energy 2 to 3.5 keV, current 0.2 to 0.4A) was injected from aboard the rocket at 100 to 150 km.At the moments the beam was injected perturbations of the near-rocket region are observed with a cross-section of about 500 m, it is much larger than the region over which the injected beam is extended.The appearance of the above region can be explained by the interaction of accelerated ions with the surroundings; the ions are generated during the positive rocket charge neutralization owing to discharge mechanisms. It is confirmed by direct measurements of the rocket potential which is about 2 kV near the apogee.