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Nonlinear Electromagnetic Waves in Dense Plasmas

Thesis Info

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Author

Jahangir, Rabia

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Plasma Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/12586/1/Rabia%20Jahangir%20Physics%202019%20qau%20isb%20prr

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726760406

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The formation and propagation of electromagnetic waves, specifically the magnetoacoustic waves are studied in this thesis for dense electron-ion magnetoplasmas. The linear and nonlinear waves such as shocks and solitons for small but finite amplitude perturbations are described for various plasma models by taking into account the quantum magnetohydrodynamic model. Further, the possible magnetoacoustic solitary wave interactions, i.e., overtaking and head-on interactions are discussed. The results are numerically analyzed by choosing the plasma parameters consistent with compact astrophysical systems. The properties of nonlinear fast magnetoacoustic waves in dense dissipative magnetoplasmas with degenerate electrons are studied theoretically. For this purpose, the quantum magnetohydrodynamic equations and the reductive perturbation technique are employed to derive the Khokhlov-Zabolotskaya- Kuznetsov (KZK) equation. The assumptions to obtain KZK equation in plasma system and the limiting cases have been identified clearly. Shock solutions of KZK equation are obtained by employing a method based upon Hirota and Clarkson-Kruskal approach. The magnetoacoustic shock waves have been examined numerically to ascertain how the plasma parameters such as ion kinematic viscosity, number density and magnetic field alter the characteristics and dynamics of shock waves. The propagation characteristics of magnetoacoustic shock waves are further investigated in a dense magnetoplasma with spin-1/2 electrons and geometrical effects by deriving the planar Korteweg-de Vries Burgers (KdVB) and cylindrical KdVB equations. Numerically, cylindrical KdVB equation is analyzed and it is observed that the number density, magnetic field and ion kinematic viscosity are the parameters that bring about significant modifications in the structure and propagation of magnetoacoustic shock waves. The spin effects are found to mitigate the phase speed of magnetoacoustic waves and the amplitude of shock structures in a dense magnetoplasma. The amplitude of the shock wave is observed to be greater for the case of cylindrical geometry and is found to propagate faster than that of planar shock waves. Furthermore, the numerical results are compared with the approximate analytical solution to show an excellent agreement of the results in the limit of earlier times. Overtaking interaction of fast magnetoacoustic solitons in dense magnetoplasmas is investigated. In this regard, one dimensional propagation of magnetoacoustic solitary waves in electron-ion plasmas with degenerate electrons is considered by deriving the Korteweg-de Vries (KdV) equation. Numerically, the characteristics of solitary waves are studied by varying the plasma parameters i.e., number density and magnetic field. Hirota bilinear formalism is applied to get the multi-soliton solutions and overtaking interaction of fast magnetoacoustic solitons is explored by utilizing them. It is observed that the values of the propagation vectors determine the interaction of solitary waves. The taller soliton being faster, overtakes the shorter soliton such that the amplitude of the respective solitary waves remain unchanged after the interaction, however they do experience a phase shift. Further, the head-on interaction of two magnetoacoustic solitons is studied in a dense magnetoplasma with spin-1/2 electrons and geometrical effects. The extended Poincaré- Lighthill-Kuo (PLK) technique and quantum magnetohydrodynamic equations are utilized to derive a pair of nonplanar Korteweg-de Vries equations. The PLK method is an analytical approach, which explicitly provides the relations of post collision trajectories and the phase shifts encountered by the magnetoacoustic solitons after interaction. The head-on interaction of two concentric ring solitons is numerically analysed. It is observed that the spin-1/2 effects, statistical pressure, displacement current and geometry of the system significantly modify the phase shifts encountered by the solitons. It is noticed that the increasing the number density decreases the phase shift of the colliding solitons. Furthermore, the cylindrical geometry is observed to decrease the phase shift by comparison with the planar geometry. The investigations carried out in this thesis shall hopefully equip us to comprehend the formation, propagation and interaction of magnetoacoustic solitons in dense magnetoplasmas which exist in compact astrophysical objects like white dwarfs and neutron stars.
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جس رزق سے آتی ہو پرواز میں کوتاہی

جس رزق سے آتی ہو پرواز میں کوتاہی
نحمدہ وَ نُصَلِّیْ علی رسولہ الکریم امّا بعد فاعوذ بااللہ من الشیطن الرجیم
بسم اللہ الرحمن الرحیم
معزز اساتذہ کرام اور میرے ہم مکتب ساتھیو!
آج مجھے جس موضوع پرلب کشائی کی سعادت حاصل ہورہی ہے وہ ہے:
’’جس رزق سے آتی ہو پرواز میں کوتاہی‘‘
جنابِ صدر!
انسان نے ایّام زیست گزارنے ہیں، عالم رنگ و بو میں سانس لینا ہے، اس جہاں کے اندر موجود نشیب و فراز سے اسے واسطہ پڑنا ہے، افراط و تفریط کا شکار بھی ہونا ہے، اور پھر افراط وتفریط کے گرداب سے اپنی ناؤ کی حفاظت بھی کرنی ہے، کا ئنات کی رنگینیاں، رعنائیاں اور دل آویز یاں بھی اُس کے لیے سازگار ماحول فراہم کریں گی۔ یہ سب منظر اس کی آنکھوں کے سامنے سے گزرنے ہیں۔
صدرِذی وقار!
ان انعامات الٰہیہ سے صرف وہی مستفید ہو سکتا ہے، جس میں ان کے حسین مناظر کو دیکھنے کی سکت ہو ،جس کی قوتِ سماعت مضبوط ہو، جس کے حواسِ خمسہ ان حسین و جمیل نظاروں کے لیے مستعد رہتے ہوں ،جونسیمِ صبح کی فرحت بخش ٹھنڈک محسوس کرنے کے لیے ہمہ وقت آرزومند ہو، جن کے جسم و جاں کسی اضمحلال کا شکار نہ ہوں۔
محترم صدر!
انسان کو اللہ تعالیٰ نے اشرف المخلوقات بنایا ہے، عظمت کا تاج اس کے سر پر سجایا ہے، انسان ہمیشہ اعلیٰ سے اعلیٰ اور ارفع سے ارفع کا آرزو مند رہتا ہے، اُس کا طائر غور و فکر بلند پروازی کا متمنی رہتا ہے، اُس کی اُمنگیں اور آرزوئیں عظیم سے عظیم تر ہوتی ہیں، وہ کبھی گھٹیا اور ادنیٰ حرکت کا مرتکب نہیں ہوتا۔ اُس کے حوصلے بلند اور عزائم مضبوط ہوتے ہیں۔
جنابِ صدر!
شاعرِمشرق حضرت علامہ اقبال رحمۃ اللہ علیہ انسان کو اس کی حقیقت سے...

IMPLEMENTASI TEORI BEHAVIORISME TERHADAP PEMBIASAAN MEMBACA ASMAUL HUSNA

The theory of learning behaviorism observe the change of one's behavior as a result of past experience. This theory emphasizes that the behavior is a result of the interaction between the stimulus and the response. This theory does not recognize the presence of innate intelligence or derivatives, but rather recognizes that intelligence is influenced by environmental factors. This theory can be applied in learning that requires practice, habituation and repetition. Therefore, to introduce and understand about Asmaul Husna, the theory of behaviorism can be applied in the process of habituation. The recitation of Asmaul Husna is very much contained in its role. Among them to introduce and hang students about Asmaul Husna, so students will feel closer to God if they often apply Asmaul Husna readings and will always feel that everything we do is supervised by God. Like the example of one of the traits contained in Asmaul Husna.  Based on the discussion, the problem raised is how to implement behaviorism theory to the habituation of Asmaul Husna reading.

Influence of Medium Change on Pashto Narrativization with Close Reference to English Narrativization

Influence of Medium Change on Pashto Narrativization with Close Reference to English Narrativization Pashto oral traditions, seen in comparison with literate works, are normally looked down upon, especially by the Pashtun literate society. The research hypothesizes that the contempt is due to misconception caused by the change of medium from oral to literate, and rises up to explore it inside Pashto literature, in a sequence. First, the researcher examined the change of medium from primary orality to literacy in general Pashto literature, with close reference to English literature and its crucial role in the switch over from primary orality to literacy, then narrowed down the study to those forms of oral and written Pashto literature that involved the narrative form, and then, for detailed analyses narrowed it down further to the study of a specific Pashto oral narrative, `Yousuf Khan Sherbano', in its various oral and literate versions. The thesis examined and interpreted the art of narrativization from a perspective of oral-literacy contrast, through a sequence, namely, primary orality, literacy and secondary orality. Use of intensive textual analysis of various communication theorists, linguists and psychologists is made on the subject. The inferences and insights generated by the analyses have been organized together into a fresh argument about transition in the mode of expression and its corollaries. By applying research about contrast between orality and literacy, the thesis lets the reader appreciate the true worth of Pashto oral traditions. On one hand, it revealed that oral products are not inferior to the modern literate products, but are rather different, for being the product of a different medium. When examined, the products of mediums of primary orality and literacy come out to be different, and the impact of the medium is borne by its respective literary product to such a considerable degree that it will not be justified to pass value judgment on the products of primary orality, by applying standards of literacy. On the other hand, it showed the correct mutual relationship of the mediums of primary orality and literacy. Products of primary orality and literacy can share same characteristics, in varying degrees, and they exist along a continuum. Features of one medium are not exclusively its own, but can be represented by another medium to such an extent, that it will be wrong to exaggerate the difference between the mediums of primary orality and literacy so much, as to consider them opposite poles or mutually exclusive.