Table 1 Nomenclature
From: A compact theory of magnetic nerve stimulation: predicting how to aim
Variable | Units | Description |
|---|---|---|
a, b | Regression constants describing radii at which axial field strength falls to zero | |
B | Tesla | Magnetic field strength |
Bz max | Tesla | Maximal z-axis component of magnetic field |
Cm | Farads/cm2 | Specific membrane capacitance of nerve cells |
| V/m | Vector of magnetically induced electric field |
E | V/m | Signed scalar magnitude of induced electric field around a circular path in homogeneous models |
E L | V/m | Scalar component of the voltage gradient along the path of an axon |
ΔE m | Volts | Change in transmembrane potential of an axon |
I | Amps | Coil current |
Imax | Amps | Maximum coil current in time |
L | m | Length of an axon segment |
μ0 | Henries/m | Magnetic permeability of free space |
n | Number of coil turns or fold-increase in coil current | |
Φ | Tesla⋅m2 | Magnetic flux |
R | m | Coil radius |
r | m | Radial distance from z-axis in space |
| Normalized radial distance, r/R | |
Ra | Ohms | Resistance of axoplasm |
ρ | Ohm-m | Resistivity of intracellular fluid |
S | m2 | Surface area for magnetic flux |
s | m | Span or width of cell |
t | sec | Time |
θ | Radians | Angle between induced electric field and an axon segment |
|ΔV L | | Volts | Absolute value of voltage appearing along the length, L, of axon |
x, y, z | m | Spatial coordinates |
| Spatial coordinates normalized by coil radius, R | |
x0, r0 | m | Radial distance from z-axis at which axial component of magnetic field becomes zero |