Charles C. Dyer and Peter S. S. Ip. Softening in N-body simulations of collisionless systems. The Astrophysical Journal, 409:60--67, May 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....a disk of 2,000 particles after only 1 revolution, and is visible even in a disk with 20,000 particles after a few revolutions. Discreteness noise can also introduce spurious heating of a collisionless cold disk, so that artificial disk cooling mechanisms must be introduced [68, 57] Dyer and Ip [22] note that equation (2) is physically inconsistent: particles act like Plummer distributions when they are contributing to the field, but are points when the field acts upon them, leading to a violation of Newton s Third Law and thus a violation of conservation of momentum. They fix this with a ....

Charles C. Dyer and Peter S. S. Ip. Softening in N-body simulations of collisionless systems. The Astrophysical Journal, 409:60--67, May 1993.

....with itself. Alternatively, it is possible to artificially smooth the Netwonian interaction, so that the gravitational potential between nearby bodies is bounded. This procedure also has the side effect of removing collisions which is often desirable from a numerical or physical point of view [23, 17]. We can define a smoothed Green s function, G oe (x) 1 oe G( kxk oe ) and a smoothed potential: d 2 dt 2 x s (t) GammarOE oe (x s (t) t) Gamma X q rG oe (x s (t) Gamma x q (t) m q (3) Many choices are available for the smoothed Green s function. For the tests ....

C. C. Dyer and P. S. S. Ip. Softening in N-body simulations of collisionless systems. Ap. J., 409:60-- 67, 1993.

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