Manfred Thumm – författare

This book is the first of its kind devoted to surface waves propagating across an external static magnetic field at harmonics of the electron cyclotron frequency. Based on comprehensive theoretical studies carried out over the course of about forty years, it presents unique material on various characteristics of these transverse waves, namely, dispersion properties and their dependence on numerous design peculiarities of plasma waveguides; damping due to interaction with the plasma surface (the kinetic channel) and collisions between plasma particles (the Ohmic channel); interaction with flows of charged particles moving above the plasma surface; parametric excitation due to the effect of an external radiofrequency field; and their power transfer for sustaining gas discharges. Clarifying numerous complicated mathematical issues it is a valuable resource for postgraduate students and experts in plasma physics, electromagnetic waves, and the kinetic theory of plasmas.

This book presents a comprehensive theoretical study of the electromagnetic eigenwaves propagating perpendicular to the axis of symmetry in various cylindrical waveguide-structures filled with magneto-active plasma. It is the second, updated and significantly expanded edition of our book “Surface Flute Waves in Plasmas. Theory and Applications”, published in 2014 in the “Springer Series on Atomic, Optical, and Plasma Physics”. First, the text is complemented by a study of the wave energy rotation around the axis of the waveguides. Second, excitation of these waves by an electron beam gyrating around the axis is investigated in detail. “Surface waves” means that these waves only propagate along plasma surfaces and not in uniform infinite plasmas. Their wave amplitudes decrease with going away from the plasma boundary into the plasma depth. “Flute” means that the axial wavenumbers kz of the waves in plasma cylinders are assumed to be zero, and the waves only propagate in azimuthal direction. In this case, the surfaces of constant density resemble fluted Greek columns. However, the presence of a small but finite kz can be taken into account by the method of successive approximations, using the theory of surface flute waves as zeroth approach. A variety of present applications of surface waves and possible future applications are also included.The book applies to both professionals dealing with physical and technological problems of confined plasmas and to graduate and post-graduate students specializing in the fíelds of electrodynamics, plasma physics and related applications.

This book presents a comprehensive theoretical study of the electromagnetic eigenwaves propagating perpendicular to the axis of symmetry in various cylindrical waveguide-structures filled with magneto-active plasma. It is the second, updated and significantly expanded edition of our book “Surface Flute Waves in Plasmas. Theory and Applications”, published in 2014 in the “Springer Series on Atomic, Optical, and Plasma Physics”. First, the text is complemented by a study of the wave energy rotation around the axis of the waveguides. Second, excitation of these waves by an electron beam gyrating around the axis is investigated in detail. “Surface waves” means that these waves only propagate along plasma surfaces and not in uniform infinite plasmas. Their wave amplitudes decrease with going away from the plasma boundary into the plasma depth. “Flute” means that the axial wavenumbers kz of the waves in plasma cylinders are assumed to be zero, and the waves only propagate in azimuthal direction. In this case, the surfaces of constant density resemble fluted Greek columns. However, the presence of a small but finite kz can be taken into account by the method of successive approximations, using the theory of surface flute waves as zeroth approach. A variety of present applications of surface waves and possible future applications are also included.The book applies to both professionals dealing with physical and technological problems of confined plasmas and to graduate and post-graduate students specializing in the fíelds of electrodynamics, plasma physics and related applications.

The book presents results of a comprehensive study of various features of eigen electromagnetic waves propagating across the axis of plasma filled metal waveguides with cylindrical geometry. The authors collected in one book material on various features of surface flute waves, i.e. impact of waveguide design on wave dispersion, wave damping influenced by various reasons, impact of plasma density and external magnetic field inhomogeneity on the wave, and impact of waveguide corrugation and electric current on the wave. A variety of present surface waves applications and possible future applications is also included. Using the method of successive approximations it is shown how one can solve problems, which concern real experimental devices, starting from simple models. The book applies to both professionals dealing with problems of confined plasmas and to graduate and post-graduate students specializing in the field of plasma physics and related applications.

In der heutigen vernetzten und von vielfältigen Kommunikationsmöglichkeiten gepräg­ ten Welt kommt der Hochfrequenztechnik steigende Bedeutung zu. Neben der System­ und Schaltungstechnik ist die Kenntnis der Meßverfahren und Meßsysteme der Hoch­ frequenztechnik wesentlich, beispielsweise bei Aufbau und Einsatz von Mobilfunk­ netzen oder Datennetzen. Weitere wichtige Anwendungsgebiete der Hochfrequenz­ technik, und damit auch der zugehörigen Meßtechnik, sind Sensorik, Fernerkundung, Radar und industrielle Heiztechnik. Die Meßtechnik wird hier für Komponenten, Bau­ gruppen, Subsysteme und Systeme im Frequenzbereich von einigen MHz bis in den Millimeterwellenbereich eingesetzt. Der Schwerpunkt liegt dabei im Mikrowellen­ bereich, da traditionelle Arbeitsbereiche der Hochfrequenztechnik wie die auf eine Vielzahl diskreter Filter aufbauende Sende- und Empfangstechnik durch die zu­ nehmende Integration solcher Funktionen in einzelnen integrierten Schaltungen an Bedeutung verlieren. Unter Hochfrequenztechnik soll daher im Rahmen dieses Buches in erster Linie die Mikrowellentechnik, die sich eher mit der Beschreibung verteilter Elemente und verkoppelter Systeme durch Leistungswellen und Streuparameter als mit der Spannungs-Strom-Beschreibung diskreter Elemente befaßt, verstanden werden. Der vorliegende Text entspricht in weiten Teilen der Vorlesung "Mikrowellenmeß­ technik" am Institut für Höchstfrequenztechnik und Elektronik der Universität Karls­ ruhe. Er wendet sich an Studenten der Elektrotechnik und Physik im Hauptdiplom, aber auch an Ingenieure und Wissenschaftler in der Praxis. Der Leser sollte grund­ legende Kenntnisse über die Hochfrequenztechnik besitzen, die benötigten mathemati­ schen Grundlagen gehen jedoch nicht über einfacheZusammenhänge der Fourier­ transformation hinaus. Im Rahmen dieses Buches ist besonders darauf Wert gelegt, diejenigen Meßsysteme und -methoden vorzustellen, denen man auch in der aktuellen Praxis begegnet.

Gyrotron oscillators (gyrotrons) are capable of providing hundreds of kilo­ watts of power at microwave and millimetric wavelengths. From their con­ ception in the late fifties until their successful development for various ap­ plications, gyrotrons have come a long way technologically and made an ir­ reversible impact on both users and developers. The possible applications of high power millimeter and sub-millimeter waves from gyrotrons and their variants (gyro-devices) span a wide range of technologies. The plasma physics community has already taken advantage of the recent advances of gyrotrons in the areas of RF plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as lower hybrid current drive (LHCD) (8 G Hz), electron cyclotron resonance heating (ECRH) (28-170 G Hz), elec­ tron cyclotron current drive (ECCD), collective Thomson scattering (CTS) and heat-wave propagation experiments. Other important applications of gy­ rotrons are electron cyclotron resonance (ECR) discharges for the generation of multi-charged ions and soft X-rays, as well as industrial materials process­ ing and plasma chemistry. Submillimeter wave gyrotrons are employed in high frequency, broadband electron paramagnetic resonance (EPR) spectroscopy. Additional future applications await the development of novel high power gyro-amplifiers and devices for high resolution radar ranging and imaging in atmospheric and planetary science as well as deep space and specialized satellite communications and RF drivers for next generation high gradient linear accelerators (supercolliders).

Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. “Vacuum Electronics” covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

Gyrotron oscillators (gyrotrons) are capable of providing hundreds of kilo­ watts of power at microwave and millimetric wavelengths. From their con­ ception in the late fifties until their successful development for various ap­ plications, gyrotrons have come a long way technologically and made an ir­ reversible impact on both users and developers. The possible applications of high power millimeter and sub-millimeter waves from gyrotrons and their variants (gyro-devices) span a wide range of technologies. The plasma physics community has already taken advantage of the recent advances of gyrotrons in the areas of RF plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as lower hybrid current drive (LHCD) (8 G Hz), electron cyclotron resonance heating (ECRH) (28-170 G Hz), elec­ tron cyclotron current drive (ECCD), collective Thomson scattering (CTS) and heat-wave propagation experiments. Other important applications of gy­ rotrons are electron cyclotron resonance (ECR) discharges for the generation of multi-charged ions and soft X-rays, as well as industrial materials process­ ing and plasma chemistry. Submillimeter wave gyrotrons are employed in high frequency, broadband electron paramagnetic resonance (EPR) spectroscopy. Additional future applications await the development of novel high power gyro-amplifiers and devices for high resolution radar ranging and imaging in atmospheric and planetary science as well as deep space and specialized satellite communications and RF drivers for next generation high gradient linear accelerators (supercolliders).

Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. “Vacuum Electronics” covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.