Related papers: What fuel for a rocket?
Relativistic jets carry a significant fraction of the total energy budget of a radio source, rivaling the power that is extracted through accretion. A minor part of this bulk kinetic power is transformed to radiation, possibly through…
Astrophysical jets are relativistic outflows that remain collimated for remarkably many orders of magnitude. Despite decades of research, the origin of cosmic rays (CRs) remains unclear, but jets launched by both supermassive black holes in…
High energy emission can be produced in the interaction sites of both galactic and extragalactic jets with the surrounding medium. We have developed a radiative model that accounts for the continuous injection of relativistic electrons in…
Sitnikov problem, consisting two close binaries and a third small body is considered, leading to a rapid ejection of the small body from the binaries. This mechanism is proposed as an explanation of jets in many astrophysical systems.…
A "space drive" is a hypothetical device that generates a propulsive force in free space using an input of power without the need for a reaction mass. Any device that generates photons (e.g., a laser) would qualify as a propellantless…
We find that the cold gas can be magnetically launched from the disc surface with the help of the radiation pressure if the angular velocity of the radiation pressure dominated accretion disc is greater than a critical value, which…
The mechanism by which outflows and plausible jets are driven from black hole systems, still remains observationally elusive. Notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and…
We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize…
Halo clouds have been found about the three largest galaxies of the Local Group and in the halos of nearby spirals. This suggests they are a relatively generic feature of the galaxy evolution process and a source of fuel for galaxy disks.…
We present our first attempts to formulate a thermodynamics-like description of explosions. The motivation is partly a fundamental interest in non-equilibrium statistical physics, partly the resemblance of an explosion to the late stages of…
Interaction of intense radiation from the underlying accretion disc with steady, general-relativistic jet is studied. The radiation field imparts momentum as well as energy on to the outflowing jet under Compton scattering. As a result, the…
In this paper, we provide a simplified stellar structure model for ideal gases, in which the particles are only driven by gravity. According to the model, the structural information of the star can be roughly solved by the total mass and…
A formalism to study the mode-by-mode response to the energy deposition of external hard partons propagating in a relativistic fluid is developed, based on a semi-analytical solution of conformal fluid-dynamics. The soft particle production…
A good vacuum performance in particle accelerators is vital for their successful operation. The reasons why a good vacuum is needed, together with the basics of vacuum physics and technology and the main gas sources inside the vacuum…
A theme that has come to the fore in advanced planning for long-range space exploration is the concept of "propellantless propulsion" or "field propulsion." One version of this concept involves the projected possibility that empty space…
A theme that has come to the fore in advanced planning for long-range space exploration is the concept of "propellantless propulsion" or "field propulsion." One version of this concept involves the projected possibility that empty space…
A new electrostatic ramjet space engine is proposed and analyzed. The upper atmosphere (85 -1000 km) is extremely dense in ions (millions per cubic cm). The interplanetary medium contains positive protons from the solar wind. A charged ball…
Several of the models for origin of the highest energy cosmic rays also predict significant neutrino fluxes. A common factor of the models is that they must provide sufficient power to supply the observed energy in the extragalactic…
Since the 1970s, astronomers have struggled with the issue of how matter can be accreted to promote black hole growth. While low-angular-momentum stars may be devoured by the black hole, they are not a sustainable source of fuel. Gas, which…
Modeling the outflow of planetary atmospheres is important for understanding the evolution of exoplanet systems and for interpreting their observations. Modern theoretical models of exoplanet atmospheres become increasingly detailed and…