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Dynamics of Low-Frequency Electromagnetic Waves and Nonlinear Solitary Structures in the Earth’S Ionosphere

Thesis Info

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Author

Kahlon, Laila Zafar

Program

PhD

Institute

Government College University

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1414

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725931766

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The thesis addresses the dynamics of low-frequency planetary electromagnetic (EM) waves and nonlinear solitary structures (vortices and zonal flows) in the Earth’s weakly ionized ionosphere of the E- and F-layers. The propagation of EM inertio-gravity waves in the partially ionized ionospheric E- and F-layers is considered in the shallow water approximation. Accounting of the field-aligned current is the main novelty of the investigation. Existence of two new eigen-frequencies for fast and slow EM waves is revealed in the ionospheric E-layer. It is shown that in F-layer slowly damping new type of inertial-fast magnetosonic waves can propagate. Slowly damping low-frequency oscillations connected with the field-aligned conductivity are found. Broad spectrum of oscillations is investigated. Existence of the new type of coupled EM ULF waves in the Earth’s ionospheric E-layer is revealed. It is shown that in the weakly ionized E-layer along with the prevalent effect of Hall conductivity the latitudinal inhomogeneity of both the Coriolis parameter and the geomagnetic field becomes essential for the ULF waves under the consideration. Action of these effects leads to the coupled propagation of EM Rossby and Khantadze modes on the one hand and coupled propagation of Rossby, Alfvén and Khantadze modes on the other hand. As a result the new type of dispersive Alfvén waves is revealed. Linear propagation properties of such coupled waves are given in detail. Possibility of existence of the other new coupled Internal-gravity and Alfvén EM planetary waves in the weakly ionized ionospheric E-layer is shown. Under such coupling new type of Alfvén waves is revealed. Simplified set of nonlinear equations describing the dynamics of mentioned coupled EM modes in the conductive weakly ionized E-layer is obtained: 1) spatially 2D equations in case of coupled Rossby-Khantadze and coupled Internal-gravity-Alfvén, and 2) spatially 3D equations in case of coupled Rossby-Alfvén-Khantadze modes, respectively. The possibility of self-organization of Rossby-Khantadze modes turbulent state into the nonlinear solitary vortical structures of dipole type in the non-dissipative ionosphere is shown analytically. Conditions for such self-organization are given. It is revealed that nonlinear large-scale vortices may generate the stronger pulses of the geomagnetic field (of the order of (10 4 - 10 5 nT ) ) than the corresponding linear waves. Nonlinear instability of short wavelength turbulence of mentioned coupled Rossby- Khantadze, Internal-Gravity-Alfvén, and Rossby-Alfvén-Khantadze EM planetary modes with respect to the excitation of low-frequency and large-scale perturbations of sheared zonal flow and magnetic field is revealed. The nonlinear mechanism of the instability is driven by the advection of vorticity and is based on the parametric excitation of zonal flow by four finite-amplitude coupled modes leading to the inverse energy cascade toward the longer wavelength. The corresponding driving forces along with the Reynolds stresses are stipulated by Maxwell’s stresses also. The growth rates of the corresponding instability and the conditions for driving them are determined. The possibility of generation of the intense mean magnetic field (of the order of (10 2 - 10 3 ) nT ) is shown. Obtained results undoubtedly will be useful for the interpretation of different observations on vortical motions, sheared zonal flows and magnetic field disturbances in laboratory and astrophysical plasmas.
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ملک فہد بن عبدالعزیز

آہ ! پاسبان حرم ملک فہد
یکم اگست کو دنیائے اسلام پر یہ خبر بجلی بن کر گری کہ ملک فہد بن عبدالعزیز سعودی حکومت کا تاج و تخت چھوڑ کر اس ملک الملوک کی بارگاہ کبریا میں پہنچ گئے جس کے ملک و سلطنت کو کبھی زوال نہ ہوگا اور وہ ہمیشہ قائم و باقی رہے گا، کل من علیھا فان ویبقیٰ وجہ ربک ذوالجلال والاکرام۔ [الرحمن:۲۶۔۲۷]
وہ ۱۹۹۵؁ء ہی سے بیمار چل رہے تھے، ان کی معذوری کی وجہ سے حکومت کا کاروبار بڑی حد تک ان کے بھائی اور ولی عہد عبداﷲ بن عبدالعزیز انجام دینے لگے تھے، اس سال ملک فہد کی بیماری نے شدت اختیار کرلی تو ۲۷؍ مئی ۲۰۰۵؁ء کو ریاض کے خاص شاہ فیصل اسپتال میں علاج کے لیے داخل ہوئے، مرض میں تخفیف و اضافہ ہوتا رہتا تھا، آخر یکم اگست بروز دوشنبہ داعی اجل کا پیغام آگیا، اناﷲ وانا الیہ راجعون۔
عالم اسلام اور پوری دنیا کے مسلمان ان کے انتقال سے غم زدہ اور سوگوار ہیں، ان کی ذات بڑی فیض بخش تھی، اور ان کے دریائے کرم اور جودوسخا کی بارش عام تھی، اس لیے ان کے غم میں سب کی آنکھیں اشک بار ہیں، ع عمت فواضلہ فعم مصابہ
اب ان کے بھائی عبدالعزیز نے حکومت کی باگ ڈور سنبھال لی ہے، اور لوگوں نے ان سے بیعت کرلی ہے، انہوں نے اپنے بھائی سلطان بن عبدالعزیز کو ولی عہد مقرر کیا ہے جو اس وقت تک دفاع اور سیاحت کے وزیر تھے، اﷲ تعالیٰ ان کو اپنی بھاری ذمہ داری اٹھانے کی قوت دے اور ان کی مدد کرے، ملک فہد کی تدفین منگل کے روز ۲؍ اگست کو ہوئی جس میں دنیا کے اکثر ملکوں کے سربراہوں اور نمائندوں نے شرکت کی، ہندوستان سے بھی ایک وفد جنازے میں شریک ہوا تھا۔
ملک فہد...

Fazle Haq Khayrabadi: An Extraordinary Personality

This is an account of the life and works of Fazle Haq Khayrabadi, a great but forgotten Indian Muslim religious scholar and thinker of the 19th century is presented. Coming from a family of great distinction, Fazle Haq Khayrabadi was an author, poet and philosopher who expressed himself in Arabic, Persian and Urdu. Especially relevant is the dedication and fervor with which Khayrabadi participated in all stages of the First Indian War of Independence of 1857 [also termed the Great Mutiny], for which he was exiled to the Andaman Islands by the British rulers of India, where he died in 1862. The remarkable personality of Fazle Haq Khayrabadi [17871862] has been forgotten by an ungrateful nation that does not honour its heroes but instead buries them under the debris of history. A great scholar, familiar with the diverse disciplines in the Islamic sciences, and the Imam of the Khayrabadi school of logic and philosophy, he, also a son the great Fazle Imam Khayrabadi, distinguished himself early for his intellectual prowess and strength of genius. Amazingly, such a scholar, devoted to academics, was also a fighter and participant in the War of Independence of 1857, and a member of the revolutionary council that directed its strategy. For this, he suffered imprisonment at the hands of the vengeful British, who sentenced him to hard labour in the distant Andaman Islands – where he died ‘across the black water’.

Acoustic Zoning Mapping and Prediction Modeling of Urban Zones of Peshawar

Noise is a well-known source of pollution in urban areas and recognized as one of the main and significant environmental problems and considered as the most pervasive hazardous pollution. It has detrimental effects on the health of people and becoming imposition upon human health and unjustifiable interference in the comfort and quality of modern life. Peshawar is one such area, located at the north-west of Pakistan that is experiencing high noise levels due to structural changes, extension of road networks, incessant increase in the number of vehicles and unbalanced urban development at both ends of the city. In order to check the severity of the mentioned issue, this study was carried out to quantify the noise pollution levels, effects on the health of the exposed population and effectiveness of the legislation to deal with it. The 24h acoustic survey was conducted with the Extech’s Datalogging Sound Level Meter at residential, commercial and silence zone and results were compared with the Pak-NEQS (2010) for noise. From the collected data different noise descriptors such as Leq, L1, L10, L50, L90, L99, LNP, NC, NEI and TNI both for day and nighttime were computed for all zones. Noise levels were measured at 30 residential locations, 23 commercial locations and 6 silence zone of the study area. The highest values of Leq dB (A) for daytime and nighttime for residential areas were recorded as 77.9 dB (A) and 70.9 dB (A), respectively. Similarly, for commercial areas the highest Leq for daytime was recorded as 87.2 dB (A) and for nighttime was recorded as 70.7 dB (A). Highest and lowest Leq dB (A) recorded at silence zone for daytime and nighttime were 72.3 dB (A) and 64.1 dB (A), respectively. The result showed that 90 % of residential sites, both for daytime and nighttime, 91% of commercial locations for daytime, 87% of commercial locations for nighttime, 100% silence zone for daytime and 83% for nighttime showed the values of Leq dB (A), beyond the permissible limit set out by NEQS-Pak (2010). The results of the noise indices for commercial and residential areas showed that noise fluctuates broadly and extreme fluctuations was encountered for 50% locations where, Leq values exceeded L90 by 10 dB(A) and same results were also witnessed for nighttime. However, for silence zone noise fluctuations were very little. The hourly Leq and noise indices for all residential, commercial and silence zone showed that Leq values were close to L10 values, which showed that fluctuations were broad and only at few locations extreme and little fluctuations were observed. Values of LNP and NC showed that fluctuations were high in commercial areas followed by residential and then silence zone both for day and nighttime. . Similarly, the NEI calculated for all the areas showed that maximum sites showed a value greater than 1. Similarly, high values of TNI were also recorded for all areas. Comparing Leq between different times of the day for commercial, residential and silence zones using ANOVA and Tukey statistical test at P<0.05 level a significance difference has been reported between different hours during daytime. Pearson correlation was performed and a strong positive correlation was found between Leq and L10, L50 Leq, L90, L1, L99, Max and Min noise levels for all zones. Significant effects of areas on the values of Ld, L10, L50, LNP were observed. Post hoc comparisons for Ld, L10, L50 and NC using the Tukey HSD test indicated that the mean score for the commercial areas during daytime for Ld was significantly different than residential areas but for nighttime no significant difference was found for all noise indices for any other area. From the collected data noise maps were also generated for daytime and nighttime using ArcGIS 9.3. Different acoustic zones were identified in the project area and the acoustic classification of the study area was used to classify the territory into six zones depending on the activities taking place in the areas. The HUD classification was used to identify the areas falling under different zones. The map showed that most of the areas fell under the normally unacceptable zone for daytime and normally acceptable zone for nighttime. A representative sample of population was interviewed using a questionnaire survey technique. Stakeholders such as policemen, shopkeepers, students, and drivers were selected as a target community. The results were analyzed through SEM and it indicates that exposure to noise for longer duration may cause headache, exhaustion, frustration and anxiety. However, person sensitive to noise may also experience difficulty in understanding speech and night awakenings in addition to the above mentioned diseases. These problems give rise to secondary issues like dizziness and ringing in ears. It is concluded that noise levels were quite high in urban zones of Peshawar owing to number of problems. One such problem is the lack of proper and comprehensive legislations for noise. Based on the data collected, a model to predict equivalent noise levels was proposed using SPSS version 18. For the development of the multiple linear regression model, the parameters used were two wheelers, three wheelers, four wheelers, van/Suzuki, bus/truck, carts and road width. A very low percentage of error for the data was exhibited by the proposed model. The main factor responsible for high noise levels was found to be traffic and its intensity. Ill planned fast growing traffic especially 3 wheelers and 2 wheelers were the main sources of traffic noise. In order to reduce the ill-effects of noise on the urban residents of Peshawar concrete actions from all the relevant agencies are needed to address the growing problem of noise pollution.