  HD 133880 is a rapidly rotating Bp star and host to one of the strongest
magnetic fields of any Bp star. A member of the Upper Centaurus Lupus
association, it is a star with a well-determined age of 16 Myr. Twelve new
spectra obtained from the FEROS, ESPaDOnS, and HARPS instruments, provide
sufficient material from which to re-evaluate the magnetic field and obtain a
first approximation to the atmospheric abundance distributions of various
elements. Using the new magnetic field measurements and optical photometry
together with previously published data, we refine the period of HD 133880 to P
= 0.877476 \pm 0.000009 days. The magnetic field structure was characterised by
a colinear multipole expansion from the observed variations of the longitudinal
and surface fields with rotational phase. This simple axisymmetric magnetic
field model is based on a predominantly quadrupolar component that roughly
describes the field variations. Using spectrum synthesis, we derived mean
abundances for O, Mg, Si, Ti, Cr, Fe, Nd and Pr. All elements, except Mg (which
has a uniform distribution), are overabundant compared to the Sun and are more
abundant in the negative than in the positive magnetic hemisphere. In contrast
to most Bp stars the abundance of O in HD 133880 is overabundant compared to
the solar abundance ratio. In studying the Halpha and Paschen lines in the
optical spectra we could not unambiguously detect information about the
magnetosphere of HD 133880. However, radio emission data at both 3 and 6 cm
suggests that the magnetospheric plasma is held in rigid rotation with the star
by the magnetic field and further supported against collapse by the rapid
rotation. Subtle differences in the shapes of the optically thick radio light
curves at 3 and 6 cm suggest that the large-scale magnetic field is not fully
axisymmetric at large distances from the star.
