Theoretical research has provided compelling arguments that magnetic fields play an important and perhaps essential role in the formation of stars out of clouds of material in the interstellar medium. Empirical tests of these theoretical results are very important. Possible tests are: (1) the measurement and mapping of the strengths of the magnetic fields in dense clouds by observations of the Zeeman effect on spectral lines of neutral atomic hydrogen, hydroxyl, and other molecules; (2) determination of cloud masses, sizes, kinematics, and densities by observation and mapping of millimeter-wave lines of selected molecules in order to assess the dynamical importance of magnetic fields; (3) measurement of the variation of the fractional ionization of molecular species in clouds in order to estimate the conditions for freezing the magnetic field flux; and (4) determination of the mass-to-magnetic flux ratio and its variation within a cloud. This grant supports an observational research project conducted by Dr. Richard Crutcher, at the University of Illinois, in collaboration with Dr. Thomas Troland, at the University of Kentucky, to test the current theoretical ideas in all of the areas outlined above.
