Lecture 1
... For a 25 solar mass star: 1) H fusion (main sequence) lifetime: ~10 million years 2) He fusion can last ~1 million years. 2) Carbon fusion can last ~1000 years 3) Neon fusion can last 3 years! 4) Oxygen fusion can last 4 months!! 5) Silicon fusion can last for 5 days!!! ...
... For a 25 solar mass star: 1) H fusion (main sequence) lifetime: ~10 million years 2) He fusion can last ~1 million years. 2) Carbon fusion can last ~1000 years 3) Neon fusion can last 3 years! 4) Oxygen fusion can last 4 months!! 5) Silicon fusion can last for 5 days!!! ...
Relativistic electron-positron plasmas
... 1) The structure of the shocks as a function of parameters, such as magnetization, composition, and field geometry. The processes responsible for shock formation in a collisionless plasma need to be identified, as the transition between different shock mediation mechanisms can affect the shock acce ...
... 1) The structure of the shocks as a function of parameters, such as magnetization, composition, and field geometry. The processes responsible for shock formation in a collisionless plasma need to be identified, as the transition between different shock mediation mechanisms can affect the shock acce ...
Preface
... of the physical interactions that govern the interaction of an incoming plasma (mainly the solar wind, but in some cases a magnetospheric plasma) with solar system objects. The Alfvén conference emphasized comparisons of phenomena from different, but similar, planets and moons, in order to increase ...
... of the physical interactions that govern the interaction of an incoming plasma (mainly the solar wind, but in some cases a magnetospheric plasma) with solar system objects. The Alfvén conference emphasized comparisons of phenomena from different, but similar, planets and moons, in order to increase ...
Order-of-Magnitude Physics – Solution Set 4
... So in 0.3 s, the chip releases 100 W × 0.3 s ∼ 30 J ∼ 3 · 108 erg which gets converted into the thermal energy of the air in the casing: (3k∆T /2) × nair V , where nair ∼ 3 × 1019 cm−3 (a number worth remembering). Solve for ∆T ∼ 15 K which feels about right (it’s hot in there!), and is certainly r ...
... So in 0.3 s, the chip releases 100 W × 0.3 s ∼ 30 J ∼ 3 · 108 erg which gets converted into the thermal energy of the air in the casing: (3k∆T /2) × nair V , where nair ∼ 3 × 1019 cm−3 (a number worth remembering). Solve for ∆T ∼ 15 K which feels about right (it’s hot in there!), and is certainly r ...
Partially Ionized Plasmas - Harvard
... Allows coupling between the plasma & neutral components Ions can drag along neutrals ...
... Allows coupling between the plasma & neutral components Ions can drag along neutrals ...
Powerpoint of lecture 10
... • The general definition of pressure is: the mean rate of transfer of (normal component of) momentum across a surface of unit area ...
... • The general definition of pressure is: the mean rate of transfer of (normal component of) momentum across a surface of unit area ...
Layers of the Sun (~ 75% Hydrogen ~ 25% Helium)
... In solar astronomy, the innermost part of the Sun, where energy is generated by nuclear reactions (fusion). The Sun's core has a tremendously high temperature and pressure. The temperature is roughly 15 million °C. At this temperature, nuclear fusion occurs, turning four hydrogen nuclei into a singl ...
... In solar astronomy, the innermost part of the Sun, where energy is generated by nuclear reactions (fusion). The Sun's core has a tremendously high temperature and pressure. The temperature is roughly 15 million °C. At this temperature, nuclear fusion occurs, turning four hydrogen nuclei into a singl ...
08 October: Stellar life after the Main Sequence
... Why mass is destiny: the more mass, the more fuel, but more massive stars use up their fuel at much higher rates ...
... Why mass is destiny: the more mass, the more fuel, but more massive stars use up their fuel at much higher rates ...
ng - CAPCA
... • “Wakefields” phase velocity same as drive jet • Forms immediately behind the trailing edge • Continues to oscillate after the jet passes: can accelerate particles over very long distances. [See P. Chen et al., Phys. Rev. Lett. 54, 693 (1985); talk at this Workshop] ...
... • “Wakefields” phase velocity same as drive jet • Forms immediately behind the trailing edge • Continues to oscillate after the jet passes: can accelerate particles over very long distances. [See P. Chen et al., Phys. Rev. Lett. 54, 693 (1985); talk at this Workshop] ...
impulsive electron acceleration by gravitational waves
... The evolution of the particles changes character when the direction of propagation of the GW is almost parallel to B. In this case, chaos disappears and the particles undergo large energy oscillations. As shown in Figure 2b, a particle starting even from rest ( 1) will be driven regularly to high ...
... The evolution of the particles changes character when the direction of propagation of the GW is almost parallel to B. In this case, chaos disappears and the particles undergo large energy oscillations. As shown in Figure 2b, a particle starting even from rest ( 1) will be driven regularly to high ...
Answers
... T4, whilst CNO goes as about T16. Hence, a modest increase in core temperature (higher mass star cores are hotter than lower mass) leads to a massive increase in the CNO rate, but only a modest rise in the p-p rate. ...
... T4, whilst CNO goes as about T16. Hence, a modest increase in core temperature (higher mass star cores are hotter than lower mass) leads to a massive increase in the CNO rate, but only a modest rise in the p-p rate. ...
1 In what fields are superconductors most widely used?
... power cables can only carry limited currents _________(why?). A network of ________(what?) would solve this problem because 1000 times more electric current can flow through them: smaller cables with more currents. 3 Superconductors can also be used to make a device known as superconducting quantum ...
... power cables can only carry limited currents _________(why?). A network of ________(what?) would solve this problem because 1000 times more electric current can flow through them: smaller cables with more currents. 3 Superconductors can also be used to make a device known as superconducting quantum ...
(SV) “Ionosat”: Orbital cluster
... Electric field: Quasi-stationary fields, ionic sound, 1- 1000 mV/m, DC-40 kHz MHD structures Whistlers, wide-band electrostatic noise 10-100 V/Hz1/2m, 1-200 kHz ...
... Electric field: Quasi-stationary fields, ionic sound, 1- 1000 mV/m, DC-40 kHz MHD structures Whistlers, wide-band electrostatic noise 10-100 V/Hz1/2m, 1-200 kHz ...
High Energy Observational Astrophysics
... Bremsstrahlung radiation is emitted by a charged particle accelerating under the influence of another charged particle, losing kinetic energy. Rate of acceleration determines wavelength of radiation produced. Greater acceleration produces smaller wavelength emission. In hot plasma at temperature T t ...
... Bremsstrahlung radiation is emitted by a charged particle accelerating under the influence of another charged particle, losing kinetic energy. Rate of acceleration determines wavelength of radiation produced. Greater acceleration produces smaller wavelength emission. In hot plasma at temperature T t ...
Fermi-Dirac Statistics
... existing states at the energy E will be filled with electrons. The function f(E) specifies, under equilibrium conditions, the probability that an available state at an energy E will be occupied by an electron. It is a probability distribution function. ...
... existing states at the energy E will be filled with electrons. The function f(E) specifies, under equilibrium conditions, the probability that an available state at an energy E will be occupied by an electron. It is a probability distribution function. ...
Fermi-Dirac Statistics
... existing states at the energy E will be filled with electrons. The function f(E) specifies, under equilibrium conditions, the probability that an available state at an energy E will be occupied by an electron. It is a probability distribution function. ...
... existing states at the energy E will be filled with electrons. The function f(E) specifies, under equilibrium conditions, the probability that an available state at an energy E will be occupied by an electron. It is a probability distribution function. ...
The Interior Structure of Neutron Stars
... Neutron drip proceeds from ρdrip=(4.3)(1014)kg/m3 until all nuclei have dripped free of nuclei by ρnuclear=(2.7)(1017)kg/m3 At very slightly higher densities we reach the muon Fermi energy and these will be created & we have neutron fluid + proton fluid + electrons + muons There are other complicati ...
... Neutron drip proceeds from ρdrip=(4.3)(1014)kg/m3 until all nuclei have dripped free of nuclei by ρnuclear=(2.7)(1017)kg/m3 At very slightly higher densities we reach the muon Fermi energy and these will be created & we have neutron fluid + proton fluid + electrons + muons There are other complicati ...
23sun4s
... Chemical energy (burning) -Kelvin-Helmholtz contraction (gravitational energy) -Nuclear Fusion Reactions -- ...
... Chemical energy (burning) -Kelvin-Helmholtz contraction (gravitational energy) -Nuclear Fusion Reactions -- ...
By what process do most stars release energy? A. Electromagnetic
... Nuclear energy can be generated by ssion or fusion. Fusion is not currently being used in reactors as an energy source. Why is this? A. ...
... Nuclear energy can be generated by ssion or fusion. Fusion is not currently being used in reactors as an energy source. Why is this? A. ...
Plasma Seminar 4/23/07 "Negative Ion Plasmas"
... • why does it exist? first electron in H only partially shields the nuclear charge ...
... • why does it exist? first electron in H only partially shields the nuclear charge ...
Radiative energy transport
... Still looks quite simple: sum of the intensity which escaped absorption and the emitted intensity. If S is known, easy to integrate. Note: if source function depends on intensity – integral equation, much more difficult, since can depend on wavelength. ...
... Still looks quite simple: sum of the intensity which escaped absorption and the emitted intensity. If S is known, easy to integrate. Note: if source function depends on intensity – integral equation, much more difficult, since can depend on wavelength. ...
Sources of energy and the origin of the chemical elements
... When the triple-α process in a red-giant is complete, the star core starts contracting. For a main sequence mass of M < 4 M¤ there is not enough energy to ignite the carbon fusion process, thus the collapse keeps going until it is halted by the pressure arising from electron degeneracy. From the st ...
... When the triple-α process in a red-giant is complete, the star core starts contracting. For a main sequence mass of M < 4 M¤ there is not enough energy to ignite the carbon fusion process, thus the collapse keeps going until it is halted by the pressure arising from electron degeneracy. From the st ...
Beyond Ideal MHD - Harvard-Smithsonian Center for Astrophysics
... Some heating mechanisms primarily affect either ions or electrons There will be separate energy equations for ions and electrons I ...
... Some heating mechanisms primarily affect either ions or electrons There will be separate energy equations for ions and electrons I ...
Polywell
The polywell is a type of nuclear fusion reactor that uses an electric field to heat ions to fusion conditions. It is closely related to the magnetic mirror, the fusor, the biconic cusp and the high beta fusion reactor. A set of electromagnets generates a magnetic field which traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. If the ions collide in the center, they can fuse.The polywell is one of many devices that use an electric field to heat ions to fusion conditions. This branch of fusion research is known as inertial electrostatic confinement. The polywell was developed by Robert Bussard, as an improvement over the fusor. His company, EMC2, Inc., developed the initial devices for the U.S. Navy.