Anthony Peratt and Gerrit Verschuur suggested that interstellar neutral hydrogen emissions bore the signature of critical velocity ionization,. A 2001 review of the phenomenon by Shu T. Lai reports that ".. laboratory experiments, and computer simulations have all shown CIV as feasible and reasonably understood, although all CIV experiments in space have yielded negative results with perhaps three exceptions". Also in 2001, C. Konz, et al., ".. discuss the critical velocity effect as a possible explanation for the observed Hα emission [..] in the Galactic halo near the edges of cold gas clouds of the Magellanic Stream" Theory development Mathematically, the critical ionization velocity of a neutral cloud, that is, when the cloud begins to become ionized, is when the relative kinetic energy is equal to the ionization energy, that is: where eVion is the ionization potential of the atoms or molecules in the gas cloud, m is the mass, v is the velocity. The phenomenon is also called the Critical velocity ionization, and also Critical velocity effect,. Alfvén considered a neutral gas cloud entering the Solar System, and noted that a neutral atom will fall towards the Sun under the influence of gravity, and its kinetic energy will increase. If their motion is random, collisions will cause the gas temperature to rise, so that at a certain distance from the Sun, the gas will ionize. Alfvén writes that the ionization potential of the gas, Vion, occurs when: that is, at a distance of: (where ri is the ion distance from the Sun of mass M, m''' is the atom weight, Vion is in volts, k is the gravitational constant). Then when the gas becomes ionized, electromagnetic forces come into effect, of which the most important is the magnetic force which is usually greater than the gravitational force which gives rise to a magnetic repulsion from the Sun. In other words, a neutral gas falling from infinity toward the Sun is stopped at a distance ri where it will accumulate, and perhaps condense into planets. Alfvén found that by taking a gas cloud with an average ionisation voltage of 12 V, and average atomic weight of 7, then the distance ri is found to coincide with the orbit of Jupiter. The critical ionization velocity of hydrogen 50.9 x 105 cm/s (50.9 km/s), and helium is 34.3 x 10 5cm/s (34.3 km/s). Background Alfvén discusses his thoughts behind critical velocity, in