  The Dirac equation is one of the most fundamental equations of modern
physics. It is a spinor equation, but some tensor equivalents of the equation
were proposed previously. Those equivalents were either nonlinear or involved
several components of the Dirac field. On the other hand, the author showed
previously that the Dirac equation in electromagnetic field is equivalent to a
fourth-order equation for one component of the Dirac spinor. The equivalency is
used in this work to derive a linear tensor equivalent of the Dirac equation
for just one component. This surprising result can be used in applications of
the Dirac equation, for example, in general relativity or for lattice
approximation of the Dirac field and can improve our understanding of the Dirac
equation.
