# Angle between proton velocity and B-field

• member 731016
In summary, the angle between proton velocity and B-field, also known as the pitch angle, is the angle between the direction of the proton's velocity and the direction of the B-field. This angle has a significant impact on the motion of charged particles in a magnetic field, with a 0 degree angle resulting in a circular path and increasing angles leading to more elliptical paths. The pitch angle can change as the particle moves through the magnetic field due to interactions with other particles or changes in the field's strength or direction. It can be measured using various methods, including particle detectors and simulations, and has important applications in fields such as plasma physics, astrophysics, and fusion energy research.
member 731016
Homework Statement
Please see below
Relevant Equations
F = qV x B
For this problem,

The solution is,

However, this may seem like a silly question, but do we need both angles?

Many thanks!

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The two angles are supplementary. Either one is correct if you only have the magnitude of the cross product.

member 731016
kuruman said:
The two angles are supplementary. Either one is correct if you only have the magnitude of the cross product.
Thank you @kuruman !

## 1. What is the angle between proton velocity and B-field?

The angle between proton velocity and B-field is known as the pitch angle. It is the angle between the direction of motion of a charged particle (such as a proton) and the direction of the magnetic field it is moving through.

## 2. How is the angle between proton velocity and B-field calculated?

The pitch angle can be calculated using the formula θ = tan-1(v/v||), where v is the velocity component perpendicular to the magnetic field and v|| is the velocity component parallel to the magnetic field.

## 3. What factors affect the angle between proton velocity and B-field?

The angle between proton velocity and B-field can be affected by the strength of the magnetic field, the speed of the charged particle, and the direction of the magnetic field relative to the direction of motion of the particle. It can also be affected by any external forces acting on the particle.

## 4. Why is the angle between proton velocity and B-field important in plasma physics?

The pitch angle is an important parameter in plasma physics as it determines the behavior of charged particles in a magnetic field. It affects the trajectory and energy of the particles, as well as their interactions with other particles and the overall dynamics of the plasma.

## 5. How does the angle between proton velocity and B-field impact space weather?

The pitch angle is an important factor in the study of space weather as it affects the movement and distribution of charged particles in space. It can impact the intensity and direction of particle flows, which can have implications for satellite operations and human space travel.

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