# What is the order of magnitude forces due to Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare?

What in order of magnitude does pressures vary in LEO due to diamagnetic repulsion of Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare on an ideal satellite?

Is there any graphs that shows the differences of magnitude in relation to altitude?

• @uhoh how is this?
– Muze
Mar 12 '19 at 1:53
• looks good to me. By the way using the @ doesn't notify people unless they've already commented on the post or edited it. https://meta.stackexchange.com/q/43019/303080
– uhoh
Mar 12 '19 at 2:21

Here is a nice graph of part of what you are asking for. It's from the book Satellite Orbits; Models, Methods, Applications by Oliver Montenbruck and Eberhard Gill, Springer, 2000. The figure and description can also be found in google books.

It shows the magnitude of some major perturbations acting on a satellite in earth orbit from LEO to GEO. This paper states the following on drag due to induced currents: (Beard, D. B., and F. S. Johnson (1960), Charge and magnetic field interaction with satellites, J. Geophys. Res., 65(1), 1–8)

"The magnetic drag resulting from the induced currents is proportional to the cube of the satellite dimensions and may exceed the mass drag for satellites larger than 50 meters in diameter; this can occur only above 1200‐km altitude, where the charge density exceeds the neutral density. Thus the magnetically induced current is an insignificant cause of drag."

(I don't have full access to the article but this is taken from the abstract)

It's therefore pretty safe to assume this perturbation to be negligible.

• Thinks like diamagnetic repulsion will require a separate calculation. - but we can conclude the effects will be on the order of 10^-15 m/s or they would have been shown in the graph. Mar 12 '19 at 11:38
• @AlexanderVandenberghe I knew of an existing i.stack.imgur.com source for the plot (I've used it twice in the past) so I included here as well, since it credits the author directly. Added a few more words as well, I hope you don't mind.
– uhoh
Mar 12 '19 at 11:48
• @Hobbes I believe I have found a source that confirms that it is indeed negligible. I added it to the answer Mar 12 '19 at 12:09
• @uhoh Yes if someone could draw a line on there for diamagnetic repulsion.
– Muze
Mar 12 '19 at 15:42