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केंद्र

डॉ. के.एस.कृष्‍णन भूचुंबकीय अनुसंधान प्रयोगशाला(KSKGRL) इलाहाबाद (उ.प्र.)

 

डॉ. के.एस. कृष्‍णन भूचुंबकीय अनुसंस्‍थान प्रयोगशाला इलाहाबाद का 27 मार्च 2008 को उदघाटन हुआ । मुख्‍य अतिथि डॉ. टी. रामस्‍वामी, सचिव, विज्ञान एवं प्रौद्योगिकी विभाग ने उदघाटन फलक का अनावरण किया । इस अवसर पर संस्‍थान की शासी परिषद के अध्‍यक्ष एवं सदस्‍य, विज्ञान तथा प्रौद्योगिकी विभाग के वित्‍तीय सलाहकार, RAC सदस्‍य, संस्‍थान के निदेशक आदि गणमान्‍य व्‍यक्‍ति उपस्‍थित थे । निदेशक , भा.भू.सं. ने इलाहाबाद में केएसकेजीआरएल की, ठोस पृथ्‍वी तथा भूअंतरिक्ष मौसम अनुसंधान से संबंधित बहु-आयामीय अध्‍ययनों के लिए प्रयोगों की विभिन्‍न श्रेणी की स्‍थापना तथा विकास की आवश्‍यकता पर बल दिया । केएसकेजीआरएल की गतिविधियों में भूचुंबकत्‍व अनुसंधान, ऊपरी वायुमंडलीय अध्‍ययन, पुराचुंबकीय तथा चुंबकीय-शैलवैज्ञानिक अध्‍ययन के क्षेत्र शामिल हैं । इन अन्‍वेषणों से पृथ्‍वी के गहरे आंतरिक तथा ऊपरी वायुमंडल तथा सौर स्‍थलीय संबंधों के बारे में महत्‍वपूर्ण सूचना मिलने की संभावना है । केएसकेजीआरएल विषुवतीय आयनन अवगति के शीर्ष पर स्‍थित है इसलिए यहॉं लिए गए प्रेक्षणों से निम्‍न अक्षांशीय क्षेत्र में, ऊपरी वायुमंडल के अध्‍ययन के लिए महत्‍वपूर्ण डाटा संसाधन प्राप्‍त होगा । केएसकेजीआरएल का भौगोलिक समन्‍वय 25.24o N, 81.5o E है तथा यह तकरीबन 40 एकड़ में फैला है ।

केएसकेजीआरएल का एक मुख्‍य कार्य यह है कि, पृथ्‍वी के चुंबकीय क्षेत्र का अबाधित रिकार्डिंग करना । केएसके जीआरएल में एक डिजिटल फ्लक्‍सगेट मैग्‍नेटोमीटर लगाया गया है जो पृथ्‍वी के चुंबकीय क्षेत्र के तीन घटकों (क्षैतिज(H), उदग्र(Z), तथा दिक्‍पात(D) का उच्‍च वियोजन में डिजिटल डाटा रिकार्ड करता है । इन प्रेक्षणों को डिक्‍लाइनेशन इन्‍क्‍लाइनेशन मैग्‍नेटोमीटर (DIM) तथा प्रोटोन प्रिसिशन मैग्‍नेटोमीटर (PPM) से किए गए निर्बाध क्षेत्र घटकों के नियमित प्रेक्षणों से संपूरित किया जाता है । संग्रहित किए गए ऑंकडे नवी मुंबई स्‍थित भा. भू. सं. मुख्‍यालय को अनुसंधान क्षेत्र में उपयोग के लिए भेजे जाते हैं ।

The scientific activities at KSK GRL, IIG is carried out in the following areas:

(A) Upper Atmospheric Studies: Because of unique location of Allahabad on equatorial ionization anomaly crest, following experiments are being carried out at KSK GRL for upper atmosphere/space weather studies.

1)Ionosonde and VHF scintillation receiver for ionospheric research:
A Canadian Advanced Digital Ionosonde (CADI) state of the art, flexible, full-featured ionosonde ideal for both routine ionospheric monitoring and research is been continuously operated at the centre. It is a radar system for determining the vertical height at which the ionosphere reflects signals back to earth in frequency range of 2 – 20 MHz and is used to compute Ionospheric parameters such as foE, foEs, foEbs h’F and foF2. Also a Spaced receiver VHF scintillation experiment is run to generate a comprehensive database of ionospheric scintillation and processed indices of scintillations. To study the morphology of scintillation producing ionospheric irregularities over Allahabad, to study the geomagnetic effects on the scintillation and to determine the zonal and random velocity of the irregularity diffraction patterns and space weather effect on it.

2) Very Low Frequency (VLF) receiver:
For the Ionosphere/Magnetosphere studies using low-latitude ground based VLF/Whistler waves observations, a VLF receiver is being operated continuously at KSK GRL for monitoring of VLF waves having their origin in natural and artificial sources. This stations works in tandem with two other IIG's VLF stations at Nainital & Varanasi and under collaboration with AWESOME (Atmospheric Weather Educational System for Observation and Modeling of Effects) network of VLF stations spread all over the globe . The VLF receiver utilizes two crossed magnetic loop antennas oriented in North/South (N/S) and East/West (E/W) direction and signal conditioning electronics that provide a flat frequency response between ~ 300 Hz and 47 kHz. The obtained data is sampled at 100 kHz and has 10-microsecond absolute time resolution. The analysis of Extremely Low Frequency (ELF, 30-3000 Hz) and Very Low Frequency (VLF, 3-30 kHz) wave data is a powerful tool for remote sensing of processes in the ionosphere and magnetosphere, providing data complementary to other techniques in space weather studies. Continuous monitoring of these waves allow for the quantitative physical analysis of electromagnetic phenomena in the ionosphere and magnetosphere such as: Lightning discharges (radio atmospheric), Whistlers, VLF emissions, Lightning induced electron precipitation (LEP), Gamma-ray bursts, Transient Luminous Events (TLE's), solar flares and Earthquake precursor studies.

3) Airglow Research:
Nightglow emissions (mainly OI 630 nm, OI 557.7 nm, OI 777.4 nm, NaD 589.3 nm, OH Meinel Band and O2 Atmospheric band) are monitored from the ground using a high resolution Imager as well as a scanning photometer on clear moonless nights. Collected Nightglow data is used to study the dynamics of the mesosphere-lower thermosphere-ionosphere region. Atmospheric temperatures of the upper mesosphere-lower thermosphere region are being derived from the observations of OH Meinel band and O2 Atmospheric band nightglow. Airglow is the emission of photons from atmospheric species excited directly or indirectly by solar electromagnetic radiation. This phenomena occurring during night is referred to as the nightglow. Nightglow emissions are the characteristic feature of the mesosphere-lower thermosphere region and the upper thermosphere region. These emissions are due to the presence of highly reactive chemical families (mainly odd-oxygen, Ox and odd-hydrogen, HOx family) in the mesosphere-lower thermosphere and the recombination processes in the upper thermosphere.

4) ULF/ELF Studies:
The institute runs the major project “ULF/ELF waves at low latitudes" under which it is planned to establish a chain of induction coil magnetometers covering the latitudinal extent of India. The instrument is based on the Faraday’s law of electromagnetic induction and measures the variation in the Earth’s magnetic field. The instrument consists of three sensors (coils) deployed in North-South, East-West and vertical directions. These coils measure three orthogonal components of geomagnetic field variations. The signal output of all the three sensors are brought to the communication unit (Cam-unit) which is the interface between the sensor and the computer in which data is collected. The time synchronization is obtained using the GPS-antenna. The data thus obtained could be used to examine the characteristics of geomagnetic pulsations at low latitudes. The data collected at the sampling rate of 64 Hz and more could also be used to study the characteristics of Schumann resonances which are lightening generated global resonant modes operating in the Earth-ionosphere cavity. Allahabad is among one of the proposed chain of stations covering the Indian latitude extent.

5) Troposphere-Ionosphere Interaction studies using Microbarograph:
We are studying the coupling between lower and upper atmosphere at equatorial latitude station Tirunelveli and intend to study this phenomena at Allahabad. The lower atmospheric variability is being studied using microbarograph and meteorological parameters such as temperature, wind variation, wind velocity etc. The upper atmospheric variations have been studied by using Ionosonde. We study the changes in lower as well as upper atmospheric variations in various atmospheric conditions including cyclone, lightning, magnetic storm etc. The atmospheric gravity wave is being measured with the help of microbarograph. The amplitude of the gravity waves varies in different atmospheric conditions and it is useful for the identification of various atmospheric processes.

(B) Solid Earth Studies: At KSK GRL following groups are dedicated to solid research:

1) Palaeomagnetic Studies:
Palaeomagnetic and rock magnetic group of KSK GRL (IIG) has been active in making significant research contributions in the areas of palaeomagnetism, rock magnetism and low filed anisotropy of magnetic susceptibility (AMS) on the intrusive bodies of the Deccan Traps and Precambrian dykes intruding into the Dharwar, Bastar and Bundelkhand Cratons, defining the magma flow dynamics and their palaeomagnetic ages. The detailed investigations, covering the entire Deccan Volcanic Province, constrained the age as 65 Ma for the Deccan volcanism. The group has also defined the apparent polar wander path (APWP) of the Indian subcontinent for the period ranging from 2000 Ma to 2500 Ma. Through AMS investigations on the Precambrian dykes, magma flow directions have been determined to locate the magma chambers and to understand the dyking mechanism. NW-SE trending structural grain of the Hyderabad granitic pluton has been successfully identified by the AMS investigations (Fig.1). The group has also identified a unique signature of remagnetization on the sediments of Bhima Basin, southern India. Two different magmatic events at 120 Ma and 65 Ma were identified for the intrusive of the Gondwana Basin. The group is also active in rock magnetic and environmental magnetic studies on the Quaternary soils of Pune and Allahabad regions to distinguish the pollution sources. The group has carried out environmental magnetic studies on the deep sea core sediments of Arabian Sea and Bay of Bengal to understand the provenance as well as palaeo climates. The group has also been active in magnetostratigraphic investigations to identify the oil potential zones of north-east India. Apart from the in-house projects, several research projects funded by DST and ONGC were successfully completed. At present three DST funded projects are on hand in collaboration with other research institutes as well as universities. The group has been imparting training to the university students in pursuing their research degrees. The group is in forefront in publishing good number of research papers in the fields of palaeo, rock and environmental magnetism.

2) Petrological, Geochemical and Isotopic Studies:
The petrological laboratory of KSKGRL is engaged in the doing the detail petrogarphy of all types of rocks including the studies of magnetic minerals which is help in paleomagnetic studies. The petrological laboratory has section cutting machine and petrological microscope. At present petrological laboratory include the advanced instruments like: (a) BUEHLER Meta-serv 3000 family offers a combination of performance, economy and reliability for most Micro structural analysis applications. It is designed for manual grinding and polishing, as well as for semiautomatic operation combined with a Vector LC power head. (b) BUEHLER Petro-thin Re-sectioning & grinding in a single system thin sectioning system is a precise, easy-to-use instrument for thin sectioning a wide variety of geological specimens, such as rocks and minerals (c) Olympus BX 51 TRINOCULAR POLARIZING Microscope with petrogaphic attachment for doing petrography and identification of mineral assemblage can magnifying up to 40X. On the basis of JNOPTIK Germany, High quality 1/2” 3.15 mega pixel color CMOS camera can capture the image live as well as still photograph of minerals

3) Crustal deformation studies:
The GPS wing at KSKGRL co-ordinates with the main group at Headquarters in the study for crustal deformations of several regions in Northern India. The continuous GPS observations can lead to the precise positioning of the site for crustal deformation studies. These observations when augmented by campaign observations at regular intervals can patch up for good coverage. Monitoring the strain build-up can demarcate the seismic prone regions and defining the active fault regions. Fore-warning of natural hazards is the ultimate aim of deformation analysis.



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