Simple magnetic field circular motion problem

[letsgo]

There's basically a beam of protons moving in the x-y plane, 30 degree from the +x-axis. The magnetic field is oriented in the +z-axis. So would the particle's motion be circular or helical?

I say helical, because the velocity isn't completely perpendicular.
Is this correct?

 

[haruspex]

If the velocity is not perpendicular to the field, what angle to you think it makes, and why?

 

[letsgo]

Okay, is it 90? So then it means it is circular? Since even though its 30 degrees from the x-axis, its still perpendicular to the B-field?

 

[haruspex]

Okay, is it 90? So then it means it is circular? Since even though its 30 degrees from the x-axis, its still perpendicular to the B-field?

Yes, it should describe a circle in the XY plane.