Electric Force

	The Electric Force node is also only available when Newtonian or Newtonian, first order is selected as the Formulation in the physics interface Particle Release and Propagation section.

Use the node to define the electric part of the Lorentz force. The particles are accelerated in the parallel or antiparallel to the electric field depending on their charge. The force is specified via an electric potential or the electric field. For cases where the field was computed in the frequency domain, the force can be computed by multiplying the field by the phase angle. Additionally, piecewise polynomial recovery can be used, which can give a more accurate representation of the specified electric field.

Select an option from the list: (the default) or .

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For enter values or expressions in the table for the E (SI unit: V/m) based on space dimension. If the electric field is computed by another physics interface then it can be selected from the list.

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For enter a value or expression for V (SI unit: V). If the electric potential is computed by another physics interface then it can be selected from the list.

Select an option from the list: (the default), , or .

The default, , does not modify the electric field when computing the force on the particles. This is appropriate for any of the following cases:

Select when the field was computed using a Frequency Domain or Eigenfrequency study. The field is multiplied by a sinusoidal phase factor,

where E (SI unit: V/m) is the electric field value used to compute the force,

(SI unit: V/m) is the complex-valued electric field computed in the previous study, and ω (SI unit: rad/s) is the angular frequency. The angular frequency can be taken directly from the previous Frequency Domain or Eigenfrequency study, or it can be specified directly or in terms of the period.

Select when the field was computed using a previous Time Dependent study but is assumed to repeat over subsequent time intervals. This allows the trajectories of charged particles to be computed over many periods, while only having to solve for the electric field over a single period. The field is assumed to be periodic but is not required to oscillate sinusoidally over time; in this sense, the option is a generalization of the option.

The electric force is computed using the periodic electric field Ep (SI unit: V/m), which is related to the previously computed field by

where t (SI unit: s) is the time, Δt (SI unit: s) is a user-defined time delay, and T (SI unit: s) is the period. Here mod is the modulo operator, which adds or subtracts a multiple of T from the first argument such that its value is between 0 and T.

For or , select an option from the list: (the default), , or . For , enter the ω (SI unit: rad/s). The default is 1 MHz. For , enter the T (SI unit: s). The default is 1 μs.

For , also specify the

(SI unit: rad). The default is 0.

For , also enter the Δt (SI unit: s). The default is 0.

Select the check box to smooth the electric field using piecewise polynomial recovery. This can give a much more accurate representation of the electric field as it uses information on adjacent mesh elements to reconstruct the field. If a coarse mesh is used to compute the field then this option can be especially useful.

Use the list to apply the force to specific particles. The available settings are the same as for the Force node.