Cannonball Model Research Articles

A possible universal origin of hadronic cosmic rays from ultrarelativistic ejecta of bipolar supernovae

Based on the “cannonball model” for gamma-ray bursts of Dar and De Rújula, it is proposed that masses of baryonic plasma (“cannonballs”), ejected in bipolar supernova explosions in our Galaxy are the sources of hadronic Galactic cosmic rays (CRs) at all energies. The propagation of the cannonballs in the Galactic disk and halo is studied. Two mechanisms for the acceleration of the observed CRs are proposed. The first is based on ultrarelativistic shocks in the interstellar medium and could accelerate the bulk of CRs up to the “knee” energy of 4×10 15 eV. The second operates with second-order Fermi acceleration within the cannonball. If the total initial energy of the ejected plasmoids in a SN explosion is 10 53 erg or higher, this second mechanism may explain the CR spectrum above the knee up to the highest observed energies. It is shown that together with plausible assumptions about CR propagation in the Galactic confinement volume, the observed spectral indices of the CR spectrum can be theoretically understood to first order. The model allows a natural understanding of various basic CR observations like the absence of the Greisen–Zatsepin cutoff, the anisotropy of arrival directions as function of energy and the small Galactocentric gradient of the CR density.

How solar radiation pressure acts on RSAT and VSAT with a small evolving tip-off in SELENE

The solar radiation pressure model for the sub-satellites RSAT and VSAT in the SELENE project is improved to correct the mean acceleration due to an evolving tip-off of the spin during the life time of satellites. The shape of the satellites is assumed to be a regular octagonal pillar. Solar radiation pressure force components acting on each surface element of the satellite are calculated independently and summed vectorially during a total period of Euler’s free nutation of the satellite to obtain the mean acceleration of the satellite center of mass. The Doppler tracking data reduction process for the RSAT is simulated after incorporating the modified model into the orbit analysis software. Comparing with two other types of solar radiation pressure models, the standard cannonball model and a non tip-off model, it is found that when the tip-off becomes larger than 5°/s, the orbit determination result of using the modified model is better than the results of using other ones.

The cepheid-like relationship between variability and luminosity explained within the "cannonball model"of gamma-ray bursts

I show how an empirical variability -luminosity relationship for prompt gamma-ray bursts, first proposed by Fenimore and Ramirez-Ruiz, can be understood as a special-relativistic beaming effect in the "cannonball model" of Dar and De Rújula. In this scenario the variability is a measure of the direction of propagation and the Lorentz factor of the cannonball on which in turn the apparent luminosity of the prompt GRB depends sensitively. The observed absence of cosmological time dilation in the "aligned peak test"-when using redshifts derived with this relation -is also explained. The most direct evidence in favour of the cannonball model presented here is its correct description for the observed relation between narrow-spike width and amplitude within a given GRB. There seems to be an indication for cosmological time dilation in the total duration of GRBs, as expected in the cannonball model. Quantitative predictions for the luminosity function of GRBs and the "spectral-lag luminosity relation"are given.

Solar radiation pressure model for the relay satellite of SELENE

A new radiation pressure model of the relay satellite of SELENE has been developed. The shape of the satellite was assumed to be a combination of a regular octagonal pillar and a column. Radiation forces acting on each part of the spacecraft were calculated independently and summed vectorially to obtain the mean acceleration of the satellite center of mass. We incorporated this new radiation pressure model into the orbit analysis software GEODYN-II and simulated the tracking data reduction process of the relay satellite. We compared two models: one is the new radiation pressure model developed in this work and the other a so-called “cannonball model” where the shape of the satellite is assumed to be a sphere. By the analysis of simulated two-way Doppler tracking data, we found that the new radiation pressure model reduces the observation residuals compared to the cannonball model. Moreover, we can decrease errors in the estimated lunar gravity field coefficients significantly by use of the new radiation pressure model.

Implosion Efficiency of Light Ion Beam Driven Target

The implosion efficiency of light ion beam (LIB) driven target were investigated by simulation. The results was explained by the simple cannon ball model during the early stage of the pulse when the thermal motion could be neglected.