Magnetic tape device, magnetic tape, and magnetic tape cartridge

A magnetic tape device comprising:

• a winding reel;
• a magnetic tape;
• and
• a magnetic tape cartridge including a cartridge reel,
• wherein, in the magnetic tape device,
• a control device causes the magnetic tape is caused to run between the winding reel and the cartridge reel in a state where a tension is applied in a longitudinal direction of the magnetic tape and a maximum value of the tension is at least 0.50 N,
• the magnetic tape after running in a state where the tension is applied is wound around the cartridge reel by applying a tension of 0.40 N or less in the longitudinal direction of the magnetic tape,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder, and
• the number of recesses having an equivalent circle diameter of 0.20 μm to 0.50 μm existing on a surface of the magnetic layer is 10 to 500 per 40 μm×40 μm area,
• where the number of said recesses is obtained by randomly selecting a 40 μm square measurement area from the surface of the magnetic layer,
• obtaining a plane image of the surface of the magnetic layer using an atomic force microscope,
• defining a surface of the measurement area equivalent to volumes of protrusion components and recess components as a reference surface,
• defining portions detected as portions recessed from this reference surface as recesses, provided that a portion specified as a recess may be a recess, a part of which is within the measurement area and another part of which is beyond the measurement area,
• in said plane image, measuring the area of the portions defined as recesses, and calculating the equivalent circle diameters of said recesses.