Read article on Pulsars, not clear how a sphere sources pole-only emission?

[ndvcxk]

The pole still has extremely strong gravity, how can a sphere suddenly concentrate the radiation at the pole to be emitted there ?

As this is the only exit, should there not be a strong deformation ? How does the radiation make it to the pole, or, is the radiation we are getting only from the small pole area, the rest of the surface does not supply any ?

Thx, newbie!

 

[mgb_phys]

The pulsar has very strong magnetic fields which concentrate the beams and only allow them out at the poles.

Form the wiki article http://en.wikipedia.org/wiki/Pulsar

 

[ndvcxk]

Thx for responding. In the picture the beam is way too thin, should the emission not be
way, way broader, (yet, we assume rotation is so fast).

1) Is there any possibility of replicating a magnetic-field controlled radiation emission from a sphere to form a so finely-focused beam ? (The absence of the field must be tube shaped !)

2) Is the radio-source "creeping along" the rest of the surface before it hits the poles ?

3) Or, are we only seeing the emission of the poles, nothing else.

(No, I don't think there are little green men, they would choose a pattern..)

I find astronomy, (compared to the lifesciences) highly, highly deductive, it's a bit
like a fantasy field...

 

[mgb_phys]

Thx for responding. In the picture the beam is way too thin, should the emission not be
way, way broader, (yet, we assume rotation is so fast).

The beam width would depend on the details of the magnetic field - not sure how you would measure it directly. If you knew the distance to the pulsar and measured th epulse width you could get the angle - but only if you knew the beam was aimed directly at you and so you were getting the full width. You can see the beam from an X-ray pulsar in a nebula where it lights up the surrounding gas.

2) Is the radio-source "creeping along" the rest of the surface before it hits the poles ?
3) Or, are we only seeing the emission of the poles, nothing else.

The mechanism is different in different types of pulsar but basically the whole surface is a radio source. Stuff hitting the surface is turned into a plasma that is trapped by the field, the charged plasma moving in a curved field gives you radio emission. The magnetic field blocks the radio signal everywhere except at the poles. The field at the poles is also more curved which gives the most emission.

I find astronomy, (compared to the lifesciences) highly, highly deductive, it's a bit
like a fantasy field...

There are more weird objects to consider but they are also very simple in some sense. YOu have isolated objects on their own that you can study individually - much simpler than the interrelated mechanisms in biology.